全文获取类型
收费全文 | 4334篇 |
免费 | 21篇 |
专业分类
公路运输 | 1109篇 |
综合类 | 749篇 |
水路运输 | 1365篇 |
铁路运输 | 72篇 |
综合运输 | 1060篇 |
出版年
2023年 | 7篇 |
2022年 | 33篇 |
2021年 | 17篇 |
2020年 | 18篇 |
2019年 | 24篇 |
2018年 | 375篇 |
2017年 | 363篇 |
2016年 | 394篇 |
2015年 | 38篇 |
2014年 | 64篇 |
2013年 | 356篇 |
2012年 | 190篇 |
2011年 | 379篇 |
2010年 | 389篇 |
2009年 | 162篇 |
2008年 | 321篇 |
2007年 | 208篇 |
2006年 | 61篇 |
2005年 | 104篇 |
2004年 | 74篇 |
2003年 | 87篇 |
2002年 | 53篇 |
2001年 | 32篇 |
2000年 | 52篇 |
1999年 | 32篇 |
1998年 | 35篇 |
1997年 | 34篇 |
1996年 | 38篇 |
1995年 | 60篇 |
1994年 | 13篇 |
1993年 | 37篇 |
1992年 | 25篇 |
1991年 | 22篇 |
1990年 | 15篇 |
1988年 | 9篇 |
1987年 | 15篇 |
1986年 | 18篇 |
1985年 | 17篇 |
1984年 | 15篇 |
1983年 | 15篇 |
1982年 | 13篇 |
1981年 | 20篇 |
1980年 | 13篇 |
1979年 | 22篇 |
1978年 | 16篇 |
1977年 | 12篇 |
1976年 | 16篇 |
1975年 | 13篇 |
1974年 | 9篇 |
1972年 | 9篇 |
排序方式: 共有4355条查询结果,搜索用时 15 毫秒
1.
ABSTRACTThe need for improved public transport (PT) ticketing in ever-growing deregulated PT markets has made well-designed integrated ticketing systems a priority area of intervention for PT service providers around the world. Yet, very little practical evidence of its impacts are reported in Sweden and in the world at large. The focus of this study was the impacts of the Movingo integrated ticketing scheme in terms of PT patronage, user satisfaction and the perceived quality of the ticketing set-up. Three travel surveys were conducted along the Stockholm-Uppsala route. Methods including logistic regression and correlated t-tests were used to analyse the samples. The findings suggest that the scheme made rail commuting more attractive resulting in an overall increase of about 24% in ticket sales with 3% – 15% car commuters reporting that they patronised PT services after the project. The scheme also resulted in increased rail commuter satisfaction. The overall perceived quality of the ticketing set-up did not however improve due to interoperability challenges. Service providers’ uncertainty about equitable distribution of revenue among the participating service providers, interoperability challenges and the lack of interest among most of the participating service providers to sell Movingo tickets are some issues to be addressed. 相似文献
2.
Horbachov Peter Makarichev Oleksandr Svichynskyi Stanislav Ivanov Ihor 《Transportation》2022,49(1):115-136
Transportation - Travel surveys in cities remain the main source of information for obtaining people’s trip characteristics and developing transport models that serve to predict the... 相似文献
3.
The time-series of remote-sensed surface chlorophyll concentration measured by SeaWiFS radiometer from September 1997 to December 2001 and the relevant hydrological and meteorological factors (remote-sensed sea surface temperature, atmospheric precipitation, air temperature and wind stress) in Santa Monica Bay and adjacent waters off southern California were analyzed using wavelet and cross-correlation statistical methods. All parameters exhibited evident seasonal patterns of variation. Wavelet analysis revealed salient long-term variations most evident in air temperature during El Niño 1997–1998 and in wind stress during La Niña 1998–1999. Short-period (<100 days) variations of remote-sensed chlorophyll biomass were mostly typical to spring seasons. Chlorophyll biomass was significantly correlated with air temperature and wind stress: an increase of chlorophyll biomass followed with 5–6-day time lag an increase of wind stress accompanied by a simultaneous decrease of air temperature. The mechanism of these variations was an intensification of phytoplankton growth resulting from the mixing of water column by wind stress and entrainment of nutrients into the euphotic layer. 相似文献
4.
PANG Yong-jie YOU Guang-xin 《船舶与海洋工程学报》2005,4(4):1-6
Oceanographic survey, or other similar applications should be the applications of multiple AUVs. In this paper, the skill & simulation based hybrid control architecture (S^2BHCA) as the controller's design reference was proposed. It is a multi-robot cooperation oriented intelligent control architecture based on hybrid ideas. The S^2BHCA attempts to incorporate the virtues of the reactive controller and of the deliberative controller by introducing the concept of the "skill". The additional online task simulation ability for cooperation is supported, too. As an application, a multiple AUV control system was developed with three "skills" for the MCM mission including two different cooperative tasks. The simulation and the sea trials show that simple task expression, fast reaction and better cooperation support can be achieved by realizing the AUV controller based on the S^2BHCA. 相似文献
5.
The Peoples Republic of China, with its great urban populations, is finding it necessary to develop a range of strategies to deal with increasing demand for goods and people movement, increasing motorization and the increasing congestion that results from the increasing travel demand. This paper discusses strategies being adopted in two northern cities, Changchun and Shenyang. Both transit and roadway programs are examined for Changchun. Problems and successes of a new toll road are examined for Shenyang. Sustained infrastructure investment is essential to assure the necessary mobility for economic growth. 相似文献
6.
A paper was published in the immediately previous issue of this journal describing a stated preference experiment examining how people are influenced in the selection of a departure time for a hypothetical trip to see a movie. The title was ‘A stated preference examination of time of travel choice for a recreational trip’, Volume 30(3):17–44. Numbers were used to indicate references in the text of the paper and in Table 1 accompanying the text, but these numbers were omitted from the list of references at the end of the paper - making it very difficult to identify specific citations. The list of references from the paper is reprinted below with the reference numbers included. This provides a listing that can be used in conjunction with the text of the paper and Table 1 as published to identify specific citations as intended. 相似文献
7.
8.
HE Tseng J. Asgari D. Hrovat P. van der Jagt A. Cherry S. Neads 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2005,43(3):199-216
In the pursuit of an objective rating on vehicle stability performance, it is always desirable to reduce disturbances and inconsistencies during experimental evaluations, especially the ones introduced by human drivers. This paper presents the development of a steering robot designed for closed-loop steering tasks during evasive manoeuvres. It describes the controller structure and discusses experimental results, in addition to simulation/vehicle model verifications and theoretical control analysis. 相似文献
9.
Shogo Nakasumi Katsuyuki Suzuki Daiji Fujii Hideomi Ohtsubo 《Journal of Marine Science and Technology》2003,7(4):180-188
This article presents a mixed method of analyzing shell elements and solid elements using the overlaying mesh method. In
the structural design of a ship's hull, the shell elements are used for the global model. However, the solid elements are
necessary to analyze the stress concentration zones or the vicinity of a crack. In such cases, the models are analyzed using
zooming analysis, in which the results of a global model analysis are transferred to a local model analysis by imposing boundary
conditions. This method is more advantageous than zooming analysis in terms of the accuracy of the solution and the modeling
flexibility. Some examples of a plate model with a cracked surface or with a projection are shown in order to demonstrate
the effectiveness of the method.
Received: August 6, 2002 / Accepted: November 25, 2002
Address correspondence to: S. Nakasumi (sumi@nasl.t.u-tokyo.ac.jp)
Updated from the Japanese original, which won the 2002 SNAJ prize (J Soc Nav Archit Jpn 2001;189:219–224; and 190:655–662) 相似文献
10.
Basic Analytical Study of Pantograph-catenary System Dynamics 总被引:9,自引:0,他引:9
T.X. Wu M.J. Brennan 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1998,30(6):443-456
For a high speed electrical rail system, good dynamic performance of the pantograph-catenary system is vital for smooth and continuous current collection. It has been known for many years that to achieve this the head of the pantograph should be made as light as possible and the average stiffness of the catenary should be high. These conclusions, however, have been reached by numerical modelling and operational experience. In this paper the pantograph-catenary system is modelled as a time-varying, single degree-of-freedom system to facilitate an analytical investigation of the system dynamics. Although the model is very simple, it allows physical insight into the dynamic behaviour of the system, and because the excitation is parametric it also allows the stability of the system to be investigated. The finite element method is used to determine the catenary characteristics and Floquet theory is used to analyse the behaviour of the coupled system. 相似文献