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131.
132.
M. G. Graham 《Maritime Policy and Management》1998,25(2):129-147
This article considers the perennial topic of how to acheive an equilibrium balance between stability and competition in intermodal shipping. It argues that competition is becoming destructive, but that the imbalance is difficult to correct in a climate where competitive pressures are strog everywhere and restraints on competiiton are unfashionable. In this context, pricing of intermodal services, the emergence of multi-trade alliances, the revelance of contestable market theory and developments in regulatory policies are all examimned. Some points towards restoring an equilibrium balance are offered. 相似文献
133.
New Large Aircraft (NLA) are new aircraft developments larger than any existing aircraft. The NLA's higher seat capacity will significantly impact passenger terminal design and operations. This paper focuses on the issues regarding the departure lounge. Deterministic queuing theory is used to determine the size and seating configuration of the lounge, as well as to decide whether a second level should be built to accommodate the increase in the number of passengers. The paper also discusses the use of the satellite section of a pier‐satellite terminal as a single lounge for the NLA. Spreadsheets are used to implement the analyses. 相似文献
134.
Y. H. Rim J. H. Moon G. Y. Kim S. D. Noh 《International Journal of Automotive Technology》2008,9(6):719-728
Automotive general assembly requires many manual assembly operations to be carried out by human workers. Ergonomic analysis
is an important part of the design and evaluation of products, jobs, tools, machines and environments for safe, comfortable
and effective human functioning. Most recent researches have involved the evaluation of working conditions to prevent work-related
musculoskeletal disorders. The majority of previous research on automotive companies has mainly considered the results of
ergonomic analyses such as RULA (Rapid Upper Limb Assessment), REBA (Rapid Entire Body Assessment) and OWAS (Ovako Working
Posture Analysis System). Analysis of static posture including reachability, clearances for arm, hand and tool has also been
used to evaluate working conditions. However, in addition to static posture analysis, a biomechanical analysis in dynamic
conditions should also be conducted. There are no integrated frameworks or standard schema for ergonomic analysis using digital
human models in digital environments. The purpose of this paper is to propose a new framework for the evaluation of working
conditions by ergonomic and biomechanical analysis using digital models based on XML standard schema, including: products,
processes, manufacturing resources and human workers. This paper presents the analysis results using the proposed framework
for automotive general assembly operations. We propose a new framework for the evaluation of the assembly operations and their
environments. Then we apply a digital human model to the dynamic simulation of general automotive assembly operations based
on standard schemas in XML and PPRH (Product, Process, Resource and Human). Using PPRH information based on a standard XML
schema to analyze the ergonomic and biomechanical results, the engineer can visualize, analyze and improve assembly operations
and working environments in automotive general assembly shops using digital models. 相似文献
135.
Desired yaw rate and steering control method during cornering for a six-wheeled vehicle 总被引:1,自引:0,他引:1
S. -J. An K. Yi G. Jung K. I. Lee Y. -W. Kim 《International Journal of Automotive Technology》2008,9(2):173-181
This paper proposes a steering control method based on optimal control theory to improve the maneuverability of a six-wheeled
vehicle during cornering. The six-wheeled vehicle is believed to have better performance than a four-wheeled vehicle in terms
of its capability for crossing obstacles, off-road maneuvering and fail-safe handling when one or two of the tires are punctured.
Although many methods to improve the four-wheeled vehicle’s lateral stability have been studied and developed, there have
only been a few studies on the six-wheeled vehicle’s lateral stability. Some studies of the six-wheeled vehicle have been
reported recently, but they are related to the desired yaw rate of a four-wheeled vehicle to control the six-wheeled vehicle’s
maneuvering during corning. In this paper, the sideslip angle and yaw rate are controlled to improve the maneuverability during
cornering by independent control of the steering angles of the six wheels. The desired yaw rate that is suitable for a six-wheeled
vehicle is proposed as a control target. In addition, a scaled-down vehicle with six drive motors and six steering motors
that can be controlled independently is designed. The performance of the proposed control methods is verified using a full
model vehicle simulation and scaled-down vehicle experiment. 相似文献
136.
The impact of high-speed technology on railway demand 总被引:1,自引:0,他引:1
This paper estimates a passenger railway demand function to analyse effects arising from the introduction and use of high-speed
technologies. The paper reports estimates of demand elasticities with respect to price, income, quality of service and a range
of exogenous characteristics. The results show that travel time savings from conventional high-speed technology have a larger
impact on passenger demand than tilting train technology. The introduction of conventional high-speed technology is associated
with an 8% increase in passenger railway demand. Increasing the use of either type of high-speed technology appears to induce
small positive effects on demand beyond those obtained from usual traffic density increases on non-high-speed existing technology.
Antonio Couto is an assistant professor in the Faculty of Engineering (FEUP) at the University of Porto. He received his PhD from FEUP in 2005 having completed a thesis in railway transport economics. His research focuses on issues related to transport economics and infrastructures. Daniel J. Graham is a Reader in the Centre for Transport Studies at Imperial College London. He specialises in the economics of transport, focusing in particular on modelling the implications of transport provision and accessibility for productivity and economic growth. 相似文献
Daniel J. Graham (Corresponding author)Email: |
Antonio Couto is an assistant professor in the Faculty of Engineering (FEUP) at the University of Porto. He received his PhD from FEUP in 2005 having completed a thesis in railway transport economics. His research focuses on issues related to transport economics and infrastructures. Daniel J. Graham is a Reader in the Centre for Transport Studies at Imperial College London. He specialises in the economics of transport, focusing in particular on modelling the implications of transport provision and accessibility for productivity and economic growth. 相似文献
137.
Intelligent transportation systems have been promoted as a means to improve both the efficiency and safety of the road network. The effectiveness of advanced technologies in improving road safety has been an area of research which has thus far yielded mixed results. In order to ensure that advanced technologies deliver on their intended outcomes, more research has to be devoted to understanding road users' perceptions and reactions to these systems. This study examines drivers' perceptions of the use of dynamic message signs and their self‐reported reactions to the messages displayed. In general, drivers support the use of highway electronic boards for traffic incident reports and weather information which have an impact on traffic delays and level of service. They also think that it is a good idea to display road safety messages and to remind drivers to drive safely and be courteous on the roads. Moreover, most drivers reported that they do read and think about the messages displayed and react positively to some of the road safety messages. 相似文献
138.
Deconstructing development density: Quality, quantity and price effects on household non-work travel
Smart growth and transit-oriented development proponents advocate increasing the density of new land development and infill redevelopment. This is partly in order to reduce auto use, by reducing distances between trip origins and destinations, creating a more enjoyable walking environment, slowing down road travel, and increasing the market for transit. But research investigating how development density influences household travel has typically been inadequate to account for this complex set of hypotheses: it has used theoretically unjustified measures, has not accounted for spatial scale very well, and has not investigated potentially important combinations of measures. Using data from a survey of metropolitan households in California, measures of development density corresponding to the main hypotheses about how density affects travel—activity density affecting distance traveled, network load density affecting the speed of auto travel, and built form density affecting the quality of walking—are tested as independent variables in models of auto trip speed and individual non-work travel. Residential network load density is highly negatively correlated with the speed of driving, and is also highly correlated with non-work travel, both singly and in combination with other measures. Activity density and built form density are not as significantly related, on their own. These results suggest that denser development will not influence travel very much unless road level-of-service standards and parking requirements are reduced or eliminated. 相似文献
139.
Konstantinos G. Zografos Konstantinos N. Androutsopoulos Teemu Sihvola 《Transportation》2008,35(6):777-795
Flexible transport services include a wide range of demand responsive transport systems that provide non-conventional passenger
and freight transportation services. Several alternative business models varying according to the local market conditions,
the socio-economic, legal, and institutional framework may be developed for the provision of Flexible Transport Systems (FTS).
The objective of this paper is twofold: first to present an integrated methodological framework for developing and assessing
alternative FTS business models and second to demonstrate its applicability to a case study regarding the prioritization of
alternative FTS business models for the provision of flexible passenger transport services in Helsinki.
相似文献
Teemu SihvolaEmail: |
140.
Using latent class cluster analysis, this paper investigates the spatial, social, demographic, and economic determinants of
immigrants’ joint distribution among travel time, mode choice, and departure time for work using the 2000 Census long form
data. Through a latent tree structure analysis, age, residential location, immigration stage, gender, personal income, and
race are found to be the primary determinants in the workplace commute decision-making process. By defining several relatively
homogeneous population segments, the likelihood of falling into each segment is found to differ across age groups and geography,
with different indicators affecting each group differentially. This analysis complements past studies that used regression
models to investigate socio-demographic indicators and their impact on travel behavior in two distinct ways: (a) analysis
is done by considering travel time, mode choice, and departure time for work simultaneously, and (b) heterogeneity in behavior
is accounted for using methods that identify different groups of behavior and then their determinants. Conclusively the method
here is richer than many other methods used to study the ethnically diverse population of California and shows the addition
of geographic location and latent segment identification to greatly improve our understanding of specific behaviors. It also
provides evidence that immigrants are as diverse as the non-immigrant population and transportation policies need to be defined
accordingly.
相似文献
Konstadinos G. GouliasEmail: |