全文获取类型
收费全文 | 1775篇 |
免费 | 22篇 |
专业分类
公路运输 | 683篇 |
综合类 | 63篇 |
水路运输 | 484篇 |
铁路运输 | 41篇 |
综合运输 | 526篇 |
出版年
2023年 | 19篇 |
2022年 | 39篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 18篇 |
2018年 | 53篇 |
2017年 | 54篇 |
2016年 | 101篇 |
2015年 | 22篇 |
2014年 | 89篇 |
2013年 | 279篇 |
2012年 | 94篇 |
2011年 | 99篇 |
2010年 | 92篇 |
2009年 | 93篇 |
2008年 | 98篇 |
2007年 | 51篇 |
2006年 | 41篇 |
2005年 | 30篇 |
2004年 | 30篇 |
2003年 | 18篇 |
2002年 | 22篇 |
2001年 | 24篇 |
2000年 | 33篇 |
1999年 | 27篇 |
1998年 | 16篇 |
1997年 | 27篇 |
1996年 | 28篇 |
1995年 | 33篇 |
1994年 | 13篇 |
1993年 | 17篇 |
1992年 | 18篇 |
1991年 | 16篇 |
1990年 | 8篇 |
1988年 | 13篇 |
1987年 | 7篇 |
1986年 | 11篇 |
1985年 | 18篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 9篇 |
1975年 | 13篇 |
1974年 | 8篇 |
1973年 | 6篇 |
排序方式: 共有1797条查询结果,搜索用时 15 毫秒
81.
Observing the rhythms of daily life: A six-week travel diary 总被引:2,自引:0,他引:2
Axhausen Kay W. Zimmermann Andrea Schönfelder Stefan Rindsfüser Guido Haupt Thomas 《Transportation》2002,29(2):95-124
82.
Neuro-Fuzzy Control of a Tracked Vehicle Featuring Semi-Active Electro-Rheological Suspension Units 总被引:3,自引:0,他引:3
S. B. Choi M. S. Suh D. W. Park M. J. Shin 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2001,35(3):141-162
This paper presents vibration control of a tracked vehicle installed with electro-rheological suspension units (ERSU). As a first step, an in-arm type ERSU is designed, and its spring and damping characteristics are evaluated with respect to the intensity of electric fields. Subsequently, a 16 degree-of-freedom model for a tracked vehicle equipped with the proposed ERSU is established followed by the formulation of a neuro-fuzzy controller. This controller takes account for both ride quality and steering stability by adopting a weighting parameter between two performance requirements. The parameter is appropriately determined by employing a fuzzy algorithm associated with two fuzzy variables: the vertical speed of the body and the rotational angular speed of the wheel. Control performances to isolate unwanted vibration from bump and random road excitations are evaluated through computer simulations. In addition, maximum speed of the vehicle with 6 Watt power absorption is investigated with respect to the road roughness. 相似文献
83.
Simulation Tools, Modelling and Identification, for an Automotive Shock Absorber in the Context of Vehicle Dynamics 总被引:9,自引:0,他引:9
Stefaan W. R. Duym 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2000,33(4):261-285
For purpose of simulation of vehicle dynamics, a physical model of an automotive shock absorber has been developed and implemented in several software packages for multibody simulations. In the present paper, the damper model structure is shortly elaborated together with some measurement and estimation techniques to retrieve the model parameters, possibly from dynamometer measurements only. These techniques are illustrated on a shock absorber normally used on the front suspension of a BMW series 7. 相似文献
84.
H. Minamoto S. Takezono 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2000,34(4):229-248
This paper deals with two-dimensional motion analysis of vehicles damaged due to collision. Various parts of vehicles are damaged due to collision in general. The effects of the damage in vehicle body and wheels on the vehicle motions are investigated. The center of gravity of the vehicle and the polar moment of inertia are changed by the deformation of vehicle body. Furthermore, the geometrical relations of wheels like wheelbase, treads and steering angles may be changed by damage of the wheels. Thus the vehicle loses symmetry with respect to the vehicle axis. The four-wheel vehicle model is extended to take into account the vehicle damage due to collision. The motions of damaged vehicles are compared with those of undamaged vehicles. It is found that vehicle damages have a significant influence on vehicle motion after impact. 相似文献
85.
This paper develops a conceptual framework for the generation of activity and travel patterns in the context of more general
structures and presents an integrated model system as a step toward development of an improved travel demand forecasting model
system. We propose a two-stage structure to model activity and travel behavior. The first stage, the stop generation and stop/auto
allocation models, consists of the choices for the number of household maintenance stops and the allocation of stops and autos
to household members. The second stage, the tour formation model, includes the choices for the number of tours and the assignment
of stops to tours for each individual, conditional on the choices in the first stage. Empirical results demonstrate that individual
and household socio-demographics are important factors affecting the first stage choices, the generation of maintenance stops
and the allocation of stops and autos among household members, and the second stage choices, the number of tours and the assignment
of stops to tours.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
86.
李虎松 《西安交通大学学报(英文版)》1995,(2)
REGULATIONOFPRODUCTIONOFPARATHYROIDHORMONE-RELATEDPEPTIDE(PTHrP)ANDEXPRESSIONOFITSmRNAINAHUMANLIVER-DERIVEDCELLLINELiHusong;P... 相似文献
87.
88.
This paper presents a time-series model for the spot speeds of vehicles on a road section. Based on time-series analysis techniques, the model incorporates information on the extent of existing dependency between the speeds of successive vehicles. The model for the data is chosen while relying heavily on the data, and thus emphasis is given to their special characteristics. The advantages of using the model are examined with regard to the relative speed of two successive vehicles along a road section. The results are compared with those obtained by using a model of independent observations; fewer errors are obtained with the time-series model. Therefore, it is concluded that the sequence of speed observations contains valuable information which should be incorporated into speed models. 相似文献
89.
Patrick S. McCarthy 《Transportation Research Part B: Methodological》1982,16(4):263-278
Current evidence on the transferability of disaggregate travel demand models is inconclusive. Adding to this body of research, the present analysis focuses upon the temporal characteristics of work trip behavior in the San Francisco Bay Area. Using before and after data sets associated with the BART Impact Travel Study, multinomial logit models of work trip modal choice are estimated. The results indicate that the general form and the coefficient estimates of a pre BART model are transferable in time. Moreover, when updated to reflect BART's presence, the model's predictive success and its implied elasticity measures are generally accurate, relative to those implied by reestimating the entire model on post BART data. Finally, as economic theory would predict, elasticity measures of the service related variables were found to increase over time. 相似文献
90.