全文获取类型
收费全文 | 957篇 |
免费 | 21篇 |
专业分类
公路运输 | 234篇 |
综合类 | 47篇 |
水路运输 | 284篇 |
铁路运输 | 23篇 |
综合运输 | 390篇 |
出版年
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 14篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 32篇 |
2017年 | 23篇 |
2016年 | 45篇 |
2015年 | 6篇 |
2014年 | 35篇 |
2013年 | 175篇 |
2012年 | 42篇 |
2011年 | 47篇 |
2010年 | 55篇 |
2009年 | 55篇 |
2008年 | 45篇 |
2007年 | 35篇 |
2006年 | 25篇 |
2005年 | 26篇 |
2004年 | 13篇 |
2003年 | 20篇 |
2002年 | 9篇 |
2001年 | 13篇 |
2000年 | 16篇 |
1999年 | 5篇 |
1998年 | 12篇 |
1997年 | 12篇 |
1996年 | 12篇 |
1995年 | 21篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1972年 | 4篇 |
排序方式: 共有978条查询结果,搜索用时 0 毫秒
821.
David Silcock 《运输评论》2013,33(3):263-273
The problem of deaths and injury as a result of road crashes is now acknowledged to be a global phenomenon with authorities in virtually all countries concerned about the growth in the number of people killed and seriously injured on their roads. The World Health Organization has declared that its annual World Health Day in 2004 will have the theme 'Safe Roads', and several organizations, including the World Bank and the Global Road Safety Partnership, are supporting this initiative to raise the profile of road safety in the public and political minds. 相似文献
822.
S. T. Atkins 《运输评论》2013,33(2):111-125
The possibility of experiencing attack, assault, violence, robbery, harassment or other anti‐social behaviour has become an important influence on traveller decision‐making. Fear and apprehension about personal security can affect all aspects of travel choice (e.g. choice of route, mode, time of journey, etc.), including whether to travel at all. Indeed, in some locations an informal curfew is reported to operate. However, both the degree and widespread extent of such fears indicate that unacceptable constraints on personal liberty do exist in many locations. This paper firstly reviews the extent and nature of the problem considering recorded crime statistics, reported levels of fear and apprehension when using transport facilities and subsequent modifications to travel behaviour. Secondly, a range of possible responses by transport operators, policing agencies and national and local government are examined under four broad headings: policing and staffing; situational crime prevention; social crime prevention; and the level and quality of transport service provision. It is concluded that personal security considerations need to be explicitly incorporated into decisions concerning the design, planning, operation and management of transport systems. It is also important that institutional structures exist to permit the issue both to be recognized and tackled. 相似文献
823.
T.F. Laughlin 《运输规划与技术》2013,36(3):185-200
In the face of rapidly escalating costs of aircraft fuel, since the early 1970s, the aerospace industry has embarked on a program of measures to reduce fuel consumption. This article describes an integrated set of measures which have been undertaken by Lockheed‐California to improve the fuel requirements of the Tristar, a wide‐bodied three engine medium to long range aircraft. Measures include operational changes, improvements to maintenance practices, long term hardware modifications and technological advances. 相似文献
824.
825.
This paper builds up a typical model of a parallel hybrid electric vehicle and develops model predictive controllers for this model to control the speeds and torques for fast clutch engagement with high driving comfort and low jerk. Some modified algorithms for model predictive controllers are studied to improve their ability to track the desired speed setpoints, subject to input and output constraints. 相似文献
826.
S. -B. Li X. -Q. Guan T. -L. Lu J. -W. Zhang 《International Journal of Automotive Technology》2008,9(4):483-491
An 8 degree-of-freedom (DOF) vehicle model is established to investigate the vertical vibration characteristics of an exhaust
system excited by road surface inputs. The simplification of an exhaust system relevant to the vehicle model is discussed
in detail, including the steps of exhaust modal analysis, definition of mass element, exhaust partitioning, parameter acquisition,
and simplified exhaust validation. The vehicle model is developed based on a half-vehicle model, simulated using MATLAB/SIMULINK,
and validated by comparing the simulation and experiment on various road profiles. Results show that the vehicle model effectively
represents the dynamics of the vehicle characteristic in vertical vibration. 相似文献
827.
Arvin R. Savkoor C. T. Chou 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1999,32(4):345-374
This exploratory study considers applications of active aerodynamic devices for suppressing parasitic motion and for improving the response of vehicles to steering, within the scope of the linear dynamic behaviour. A three DOF linear model is chosen to describe the side slip, yaw and roll motion of a baseline front-wheel steered vehicle. The improvements in performance of the base-line vehicle that are achievable by the application of direct yaw and roll moments are determined when either an open loop control pre-filter or a state feedback control law based on LQR design is applied. Unlike the former control, the state feedback control is unable to make the body side-slip angle vanish. The feedback control performance of each of the two moment actuators has been examined separately and then jointly. The advantages of combining the open loop and feedback dual actuator configurations are demonstrated using the two-degree of freedom control scheme. It is found that the scheme yields a spectacular performance but demands unreasonably large moments from the actuators in the context of available aerodynamic forces. On the other hand, the demand on direct yaw and roll moment of actuators is modest when the actuators are controlled using the LQR feedback only and if the control design is used to track a desired yaw rate trajectory and simultaneously to reduce the parasitic rolling motion. Significant improvements in handling and dynamic stability of a base-line vehicle can be achieved by aerodynamically generated direct yaw and roll actuator moments provided the target control performance is reasonable. The configurations of aerodynamic actuators considered are feasible for improving vehicle handling in cornering on motorways but more work remains to be done to explore alternative aerodynamic configurations that give rise to less side effects and higher lift coefficients. 相似文献
828.
Hwa-Joong Kim Young-Tae Chang Paul T. -W. Lee Sung-Ho Shin Min-Jeong Kim 《Maritime Policy and Management》2008,35(1):103-122
This paper considers a multimodal transportation problem, which is the problem of determining the transportation flow, i.e. volume of container cargoes, and the transportation mode in each trade route, for the objective of minimizing the sum of shipping and inland transportation costs. The problem takes account of two restrictions: maximum cargo volumes capacitated at each seaport and maximum number of vehicles available at each transportation mode. To solve optimally the problem, this paper employs a mixed integer programming, which is an operations research technique. A case study is performed on the container cargo data in Korea and we draw several implications to improve efficiency in the transportation of international trade cargoes in Korea. 相似文献
829.
David Tozer Andrew Penfold 《上海造船》2008,(1):1-3
集装箱贸易显著的增长不仅表现在集装箱船队的总箱数已超过1100万箱,还表现在船的大小上。今天使用中的最大的集装箱船已超过1万箱。 相似文献
830.
T. Tokoro A. Watanabe H. Kayanne K. Nadaoka H. Tamura K. Nozaki K. Kato A. Negishi 《Journal of Marine Systems》2007,66(1-4):140
We measured the air–water CO2 flux in four coastal regions (two coral reefs, one estuary, and one coastal brackish lake) using a chamber method, which has the highest spatial resolution of the methods available for measuring coastal air–water gas flux. Some of the measurements were considerably higher than expected from reported wind-dependent relationships. The average k600 values for Shiraho Reef, Fukido Reef, Fukido River, and Lake Nakaumi were 1.5 ± 0.6, 3.2 ± 0.3, 0.69 ± 0.26, and 2.2 ± 0.9 (mean ± S.D.) times larger than the wind-dependent relationships. Results were compared with current-dependent relationships and vertical turbulence intensity (VTI). VTI is an index of water-surface stirring and is calculated from near-surface vertical velocity. Although some measurements from the reefs and river closely matched those expected from wind-dependent relationships, others were considerably higher. All data were correlated with VTI and were qualitatively explained by bottom macro-roughness enhancement. In Lake Nakaumi, results tended to differ from the wind-dependent relationships, and the difference between the measured and expected gas-transfer velocity was correlated with biological DO changes and/or the intensity of density stratification. We found these factors to have important effects on coastal gas flux. In addition, the chamber method was an effective tool for evaluating coastal gas flux. 相似文献