全文获取类型
收费全文 | 77篇 |
免费 | 3篇 |
专业分类
公路运输 | 27篇 |
综合类 | 6篇 |
水路运输 | 14篇 |
铁路运输 | 2篇 |
综合运输 | 31篇 |
出版年
2024年 | 1篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2013年 | 7篇 |
2012年 | 1篇 |
2011年 | 3篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
排序方式: 共有80条查询结果,搜索用时 31 毫秒
31.
Adaptive Suspension Concepts for Road Vehicles 总被引:1,自引:0,他引:1
Dean Karnopp Donald Margolis 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1984,13(3):145-160
Most vehicle suspensions are composed of passive spring and damper devices, although improved suspension performance is possible if an active system is used to control forces or relative velocities. The complexity, power requirements, and cost of fully active suspensions have restricted their use. Various partially active suspensions have been proposed and suspensions with slow load levelers and variable dampers are in widespread use. Here we analyze a class of basically passive suspensions the parameters of which can be varied actively in response to various measured signals on the vehicle. These suspensions can come close to optimal performance with simpler means than many of the active or semi-active schemes previously proposed. 相似文献
32.
Dean Karnopp 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2002,37(2):145-156
Fully enclosed motorcycles could form the basis for extremely fuel and space efficient vehicles, but their inherent instability upon encountering even a momentary loss of traction renders them unsuitable for general use. It will be shown that a relatively simple tilt control system using a gyroscope to provide a tilt control moment is capable of stabilizing the vehicle at still stand or at speed on a very low traction surface. Furthermore, the system can achieve a coordinated turn on high traction surfaces. Since the gyro is an energy storage device, it can be used also in a hybrid system to provide extra power for acceleration and to recover some energy during braking. This relatively old idea should be reconsidered in light of the improved electromechanical devices, which have been developed recently for hybrid electric vehicles. 相似文献
33.
34.
Marco Diana 《Transportation Research Part A: Policy and Practice》2012,46(1):1-11
The importance of measuring customer satisfaction for a public transport service is apparent, even beyond more immediate marketing purposes. The present paper shows how satisfaction measures can be exploited to gain insights on the relationship between personal attitudes, transit use and urban context. We consider nine satisfaction measures of urban transit services, as expressed by a representative sample of Italian multimodal travelers (i.e. users of both private cars and public transport). We use correlations and correspondence analyses to show if and how each attribute is related to the levels of use of public transport, and how the relationship is affected by the urban context. Then we apply a recently developed method to combine ordinal variables into one score, by adapting it to work with large samples and with satisfaction measures which have a neutral point in the scale (i.e. “neither satisfied nor dissatisfied”). The resulting overall satisfaction levels and frequency of use were not correlated in our sample. We also found the highest satisfaction levels in smaller towns and the lowest ones in metropolitan cities. Since we focus on multimodal travelers, an interpretation paradigm is proposed according to which transit services must be well evaluated by car drivers in smaller towns in order to be considered a real alternative to cars. On the other hand, transit is more competitive on factual elements in larger cities, so that it can still be used by drivers, even if it is not very well evaluated. 相似文献
35.
Ehsan Shafiei Hlynur Stefansson Eyjolfur Ingi Asgeirsson Brynhildur Davidsdottir Marco Raberto 《运输评论》2013,33(1):44-70
In this article, a conceptual framework for a comprehensive evaluation of the diffusion process of alternative fuel vehicles is introduced. The framework takes into account the most influencing stakeholders, including car manufacturers, car dealers, consumers, energy supply system, fuel stations and government. The underlying mathematical models of different stakeholders are then integrated in one model of the whole energy and transport system. The hybrid modelling framework links the two powerful dynamic simulation approaches of system dynamics (SD) and agent-based (AB) modelling. Integrated modelling structure gives the potential of building more accurate and computationally efficient models for simulating the transition to sustainable mobility. We specify the integration process and the most important linking variables between various energy and transport components. Then the application of the integrated model is explained through a test case and, finally, the applicability of the hybrid AB and SD approach and its potential contribution to the models of transition to sustainable mobility will be concluded. 相似文献
36.
Studying travel-related individual assessments and desires by combining hierarchically structured ordinal variables 总被引:1,自引:1,他引:0
Ordinal measures are frequently encountered in travel behavior research. This paper presents a new method for combining them
when a hierarchical structure of the data can be presumed. This method is applied to study the subjective assessment of the
amount of travel by different transportation modes among a group of French clerical workers, along with the desire to increase
or decrease the use of such modes. Some advantages of this approach over traditional data reduction technique such as factor
analysis when applied to ordinal data are then illustrated. In this study, combining evidence from several variables sheds
light on the observed moderately negative relationship between the personal assessment of the amount of travel and the desire
to increase or decrease it, thus integrating previous partial (univariate) results. We find a latent demand for travel, thus
contributing to clarify the behavioral mechanisms behind the induced traffic phenomenon. Categorizing the above relationship
by transportation mode shows a desire for a less environmental-friendly mix of modes (i.e., a greater desire to use heavy
motorized modes and a lower desire to use two-wheeled modes), whenever the respondents do not feel to travel extensively.
This result, combined with previous theoretical investigations concerning the determinants of the desire to alter trips consumption
levels, shows the importance of making people aware of how much they travel.
Marco Diana is a permanent researcher working at the Department of Hydraulics, Transport and Civil Infrastructures of Politecnico di Torino, Italy. His research interests include the study of innovative forms of public transport services and the analysis of multimodality behaviors. Tingting Song is a Scientific Programmer at The Rockefeller University, Center for Clinical and Translational Science, Biostatistics, Epidemiology, and Research Design Core, New York, NY, USA. She works on algorithms for non-parametric methods and their applications in medical research. She maintains the muStat package on CRAN.r-project.org and the Web server on muStat.rockefeller.edu. Knut M. Wittkowski is a Senior Research Associate at The Rockefeller University and Head of Biostatistics, Epidemiology, and Research Design at its Center for Clinical and Translational Science, New York, NY, USA. His research focuses on methods, meta data, and user interfaces to integrate nonparametric statistics into research and decision support systems. 相似文献
Knut M. WittkowskiEmail: |
Marco Diana is a permanent researcher working at the Department of Hydraulics, Transport and Civil Infrastructures of Politecnico di Torino, Italy. His research interests include the study of innovative forms of public transport services and the analysis of multimodality behaviors. Tingting Song is a Scientific Programmer at The Rockefeller University, Center for Clinical and Translational Science, Biostatistics, Epidemiology, and Research Design Core, New York, NY, USA. She works on algorithms for non-parametric methods and their applications in medical research. She maintains the muStat package on CRAN.r-project.org and the Web server on muStat.rockefeller.edu. Knut M. Wittkowski is a Senior Research Associate at The Rockefeller University and Head of Biostatistics, Epidemiology, and Research Design at its Center for Clinical and Translational Science, New York, NY, USA. His research focuses on methods, meta data, and user interfaces to integrate nonparametric statistics into research and decision support systems. 相似文献
37.
液压传动课程是机械类专业的一门重要技术基础课,几年来学校通过多媒体的充分运用、教学内容结构调整和内容创新,考试方式的改革和教师的自身素质的提高等方面进行了探索与实践,提高了教学质量,较好地实现了教学目的。 相似文献
38.
This paper deals with the measurement of the network complexity of some selected shipping groups, also identifying the contribution of co-operative agreements among carriers. The empirical investigation is focused on: (i) the analysis of the distribution of the carrying capacity per range; and (ii) the comparison of that capacity with the throughput handled in the port facilities of the group. These variables are interpreted in the light of the impact that alliances have on the geographical wideness of the services supplied by each partner. This factor also allows to depict how the cultural and political origin of shipping lines affects the decision of joining an alliance and the outcomes deriving from such co-operation. 相似文献
39.
Market segmentation studies in travel behavior research are ordinarily based on socioeconomic characteristics and personality
traits. This study explores the usefulness of a different approach, where the actual overall mobility levels across different
ground transportation modes, along with desired changes in the use of cars and transit, are used as clustering variables.
Using a given mode can in fact influence the personal representation of that mode, which in turn has been proven to be a key
element in transport behaviours. We form such multimodality-based clusters from two field studies, one involving employees
of the French transportation research institute INRETS and the other a representative sample of residents of the US San Francisco
Bay Area. We find that strong users of a given mode would like to bring more balance to their “modal consumptions” by decreasing
the use of this mode more than the average, and increasing the use of the alternative mode. However, concerning ground transport
travel budgets, the desire to travel more (or less) overall seems less strongly related to the composition of the modal balance. The US dataset shows also a greater latent demand for
travel than the French one. Socioeconomic characteristics of the clusters could not explain the patterns that were found,
confirming the importance of taking into account multimodality issues in travel behavior research. Some policy implications
from these findings are finally reported.
相似文献
Patricia L. MokhtarianEmail: |
40.
Transportation - The Netherlands seems to exhibit the unique conditions that allow cycling on the country level instead of only the city level. Moreover, the national transit system seemingly... 相似文献