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991.
Transportation specialists, urban planners, and public health officials have been steadfast in encouraging active modes of
transportation over the past decades. Conventional thinking, however, suggests that providing infrastructure for cycling and
walking in the form of off-street trails is critically important. An outstanding question in the literature is how one’s travel
is affected by the use of such facilities and specifically, the role of distance to the trail in using such facilities. This
research describes a highly detailed analysis of use along an off-street facility in Minneapolis, Minnesota, USA. The core
questions addressed in this investigation aim to understand relationships between: (1) the propensity of using the trail based
on distance from the trip origin and destination, and (2) how far out of their way trail users travel for the benefit of using
the trail and explanatory factors for doing so. The data used in the analysis for this research was collected as a human intercept
survey along a section of an off-street facility. The analysis demonstrates that a cogent distance decay pattern exists and
that the decay function varies by trip purpose. Furthermore, we find that bicyclists travel, on average, 67% longer in order
to include the trail facility on their route. The paper concludes by explaining how the distance decay and shortest path versus
taken path analysis can aid in the planning and analysis of new trail systems.
Kevin J. Krizek is an Associate Professor of Planning and Design at the University of Colorado where he directs the Active Communities/Transportation Research Group. His research interests include land use-transportation policies and programs that influence household residential location decisions and travel behavior. He has published in the areas of transportation demand management, travel behavior, neighborhood accessibility, and sustainable development. He earned a Ph.D. in Urban Design and Planning and M.S.C.E. from the University of Washington in Seattle. His master’s degree in planning is from the University of North Carolina at Chapel Hill and his undergraduate degree is from Northwestern University. Ahmed El-Geneidy is a Post-Doctoral research fellow at the Department of Civil Engineering, University of Minnesota and Humphrey Institute of Public Affairs. El-Geneidy’s research interests include transit operations, travel behavior, land use and transportation planning, and accessibility/mobility measures in urban areas. He earned B.S. and M.S. degrees from the Department of Architectural Engineering at the University of Alexandria, Egypt, and continued his academic work at Portland State University, where he received a Graduate GIS Certificate and earned a Ph.D. in Urban Studies from Nohad A. Toulan School of Urban Studies and Planning. Kristin Thompson was a research assistant with ACT and currently works for Metro Transit in Minneapolis, Minnesota. 相似文献
Ahmed El-GeneidyEmail: |
Kevin J. Krizek is an Associate Professor of Planning and Design at the University of Colorado where he directs the Active Communities/Transportation Research Group. His research interests include land use-transportation policies and programs that influence household residential location decisions and travel behavior. He has published in the areas of transportation demand management, travel behavior, neighborhood accessibility, and sustainable development. He earned a Ph.D. in Urban Design and Planning and M.S.C.E. from the University of Washington in Seattle. His master’s degree in planning is from the University of North Carolina at Chapel Hill and his undergraduate degree is from Northwestern University. Ahmed El-Geneidy is a Post-Doctoral research fellow at the Department of Civil Engineering, University of Minnesota and Humphrey Institute of Public Affairs. El-Geneidy’s research interests include transit operations, travel behavior, land use and transportation planning, and accessibility/mobility measures in urban areas. He earned B.S. and M.S. degrees from the Department of Architectural Engineering at the University of Alexandria, Egypt, and continued his academic work at Portland State University, where he received a Graduate GIS Certificate and earned a Ph.D. in Urban Studies from Nohad A. Toulan School of Urban Studies and Planning. Kristin Thompson was a research assistant with ACT and currently works for Metro Transit in Minneapolis, Minnesota. 相似文献
992.
Singapore motorisation restraint and its implications on travel behaviour and urban sustainability 总被引:1,自引:0,他引:1
Piotr S. Olszewski 《Transportation》2007,34(3):319-335
The example of Singapore shows that rapid urban and economic growth does not have to bring traffic congestion and pollution.
Singapore has chosen to restrain car traffic demand due to its limited land supply. Transport policy based on balanced development
of road and transit infrastructure and restraint of traffic has been consistently implemented for the past 30 years. Combined
with land use planning, it resulted in a modern transport system, which is free from major congestion and provides users with
different travel alternatives. As the economic growth caused a substantial increase in demand for cars, several pricing policies
were introduced with the aim of restraining car ownership and usage. Growth of the vehicle population is now controlled and
potentially congested roads are subject to road pricing. These measures help to keep the roads free from major congestion,
maintain car share of work trips below 25% and keep the transport energy usage low. Although Singapore conditions are in many
aspects unique, its travel demand experience can provide useful lessons for other rapidly growing cities in Asia.
相似文献
Piotr S. OlszewskiEmail: |
993.
Do changes in neighborhood characteristics lead to changes in travel behavior? A structural equations modeling approach 总被引:5,自引:2,他引:3
Suburban sprawl has been widely criticized for its contribution to auto dependence. Numerous studies have found that residents
in suburban neighborhoods drive more and walk less than their counterparts in traditional environments. However, most studies
confirm only an association between the built environment and travel behavior, and have yet to establish the predominant underlying
causal link: whether neighborhood design independently influences travel behavior or whether preferences for travel options
affect residential choice. That is, residential self-selection may be at work. A few studies have recently addressed the influence
of self-selection. However, our understanding of the causality issue is still immature. To address this issue, this study
took into account individuals’ self-selection by employing a quasi-longitudinal design and by controlling for residential
preferences and travel attitudes. In particular, using data collected from 547 movers currently living in four traditional
neighborhoods and four suburban neighborhoods in Northern California, we developed a structural equations model to investigate
the relationships among changes in the built environment, changes in auto ownership, and changes in travel behavior. The results
provide some encouragement that land-use policies designed to put residents closer to destinations and provide them with alternative
transportation options will actually lead to less driving and more walking.
Xinyu (Jason) Cao is a research fellow in the Upper Great Plains Transportation Institute at North Dakota State University. His research interests include the influences of land use on travel and physical activity, and transportation planning. Patricia L. Mokhtarian is a professor of Civil and Environmental Engineering, Chair of the interdisciplinary Transportation Technology and Policy graduate program, and Associate Director for Education of the Institute of Transportation Studies at the University of California, Davis. She specializes in the study of travel behavior. Susan L. Handy is a professor in the Department of Environmental Science and Policy and Director of the Sustainable Transportation Center at the University of California, Davis. Her research interests center around the relationships between transportation and land use, particularly the impact of neighborhood design on travel behavior. 相似文献
Susan L. HandyEmail: |
Xinyu (Jason) Cao is a research fellow in the Upper Great Plains Transportation Institute at North Dakota State University. His research interests include the influences of land use on travel and physical activity, and transportation planning. Patricia L. Mokhtarian is a professor of Civil and Environmental Engineering, Chair of the interdisciplinary Transportation Technology and Policy graduate program, and Associate Director for Education of the Institute of Transportation Studies at the University of California, Davis. She specializes in the study of travel behavior. Susan L. Handy is a professor in the Department of Environmental Science and Policy and Director of the Sustainable Transportation Center at the University of California, Davis. Her research interests center around the relationships between transportation and land use, particularly the impact of neighborhood design on travel behavior. 相似文献
994.
Modeling residential sorting effects to understand the impact of the built environment on commute mode choice 总被引:5,自引:2,他引:3
Abdul Rawoof Pinjari Ram M. Pendyala Chandra R. Bhat Paul A. Waddell 《Transportation》2007,34(5):557-573
This paper presents an examination of the significance of residential sorting or self selection effects in understanding the
impacts of the built environment on travel choices. Land use and transportation system attributes are often treated as exogenous
variables in models of travel behavior. Such models ignore the potential self selection processes that may be at play wherein
households and individuals choose to locate in areas or built environments that are consistent with their lifestyle and transportation
preferences, attitudes, and values. In this paper, a simultaneous model of residential location choice and commute mode choice
that accounts for both observed and unobserved taste variations that may contribute to residential self selection is estimated
on a survey sample extracted from the 2000 San Francisco Bay Area household travel survey. Model results show that both observed
and unobserved residential self selection effects do exist; however, even after accounting for these effects, it is found
that built environment attributes can indeed significantly impact commute mode choice behavior. The paper concludes with a
discussion of the implications of the model findings for policy planning.
相似文献
Paul A. WaddellEmail: |
995.
在拥堵的高速公路上,合乘车辆(HOV)车道是一种高效环保的交通方式. 虽然HOV车道广受采纳,但该系统的利用效率受到质疑. 加州在全州范围内 采取了一项允许混合动力车辆使用HOV车 道的政策,以期通过鼓励驾驶员使用省油汽车来减少尾气排放,同时通过更有效地利用HOV车道的剩余通行能缓解交通拥挤. 加州橘县高速公路的路网用于研究 该政策的影响及有效性. 研究方法结合使用传统的规划模型来估计交通需求及校准的微观仿真模型来评价系统性能. 通过对系统整体性能、车道服务水平和空气质量 三方面的分析,结论表明此政策对在高峰时段没有剩余通行能力的HOV车道带来严重的负面影响. 为保证HOV车道服务质量不明显下降还能减少排放,该政策最多允许50 000辆在加州注册的混合动力车辆使用HOV车道. 相似文献
996.
A comprehensive procedure for mathematical modeling and validation of a fuel cell hybrid vehicle (FCHV) is presented in this
paper. The subsystems are modeled based on lab testing and in-field vehicle testing results from the Tongji University Start
prototype vehicle. An FCHV-SIM (fuel cell hybrid vehicle simulation) model is then developed based on the experimental data.
Model validation results confirm that the FCHV-SIM model is reasonably accurate and suitable for model-based control development. 相似文献
997.
In fuel-cell-powered vehicles, the fuel-cell system requires a thermal-management subsystem to dissipate heat released during
the reaction of hydrogen with oxygen. When the stack generates power at a high rate, a large amount of heat is also generated.
If cooling by the radiator is insufficient, a supplementary stack-cooling system is needed to maintain a safe operating temperature.
In this study, the performance of a CO2 air-conditioning unit for stack cooling was investigated under various conditions, and the relationship between cabin cooling
and stack cooling was also studied. The coefficient of performance (COP) increased from 1.9 to 2.4, with an increase in cabin-air
inlet flow rate from 0 to 8 m3/min. When the air-conditioning unit was turned off, the cooling capacity of the stack cooler was increased; correspondingly,
as the cabin-cooling capacity was increased, that of the stack cooler decreased. With an increase in ambient-air inlet temperature
from 38°C to 45°C, the COP decreased by 24%. Additionally, both the stack-cooling capacity and cabin-cooling capacity were
decreased by about 12% and 16%, respectively, due to reduced heat transfer in the gas cooler as the ambient air inlet temperature
was increased. It is expected that the experimental results can serve as a resource in designing a stack-cooling system using
a CO2 air-conditioning unit to enhance stack power generation and efficiency. 相似文献
998.
Although automobile crash test data have a comparatively large variation because of the complexity of the tests, only a limited
number of crash tests are usually conducted due to monetary and time limitations. Thus, it is necessary to control input variables
that cause the variation in test data to obtain consistent crash test results and to correctly assess the safety performance
of an automobile under development. In this study, a MADYMO model was validated deterministically to yield the head, chest,
pelvis deceleration pulses of anthropomorphic test devices and the belt load pulses similar to those from actual tests, and
it was also validated stochastically to yield means and standard deviations of the head and chest injury numbers, i.e., HIC
15
and 3 msec clip similar to those from actual tests. A stochastic analysis was conducted using the validated MADYMO model to calculate the
sensitivity of the standard deviations of the injury numbers to the standard deviations of influential input variables to
determine the most influential input variable that makes the largest contribution to the variation in the injury numbers.
Moreover, the Taguchi approach was used to determine the optimal values of the influential input variables to improve safety
performance. 相似文献
999.
J. Son B. Reimer B. Mehler A. E. Pohlmeyer K. M. Godfrey J. Orszulak J. Long M. H. Kim Y. T. Lee J. F. Coughlin 《International Journal of Automotive Technology》2010,11(4):533-539
Driving demands significant psychomotor attention and requires even more when drivers are engaged in secondary tasks that
increase cognitive workload and divert attention. It is well established that age influences driving risk. Less is known about
how culture impacts changes in attention. We conducted parallel driving simulations in the US and Korea to measure the extent
to which age and culture influence dual-task performance. There were 135 participants divided into two groups: a younger group
aged 20∼29, and an older group aged 60∼69. Whereas some differences by culture appeared in absolute control measures, the
younger participants showed similar mean velocity and compensatory patterns associated with increased cognitive load in the
urban setting; however, the results from the older samples were less similar. 相似文献
1000.
D. García-Pozuelo Ramos A. Gauchía B. L. Boada V. Díaz 《International Journal of Automotive Technology》2010,11(5):691-699
Vehicle systems such as the steering, brakes and suspension greatly influence vehicle safety. Therefore, these systems must
be inspected to guarantee that they are functioning correctly and to certify that the vehicle is functioning at a satisfactory
safety level. In disc brakes, warping is one of the principal reasons for vibrations and noise, and it contributes to diminished
brake efficiency. Currently, the International Motor Vehicle Inspection Committee (CITA) demands disc brake warping inspections
occur during periodic motor vehicle inspections (PMVIs); however, the procedure to carry out this inspection is not well defined.
In this investigation, the warping phenomenon has been analyzed, and a new inspection procedure is proposed. 相似文献