全文获取类型
收费全文 | 869篇 |
免费 | 5篇 |
专业分类
公路运输 | 189篇 |
综合类 | 64篇 |
水路运输 | 284篇 |
铁路运输 | 39篇 |
综合运输 | 298篇 |
出版年
2022年 | 13篇 |
2021年 | 10篇 |
2020年 | 10篇 |
2019年 | 11篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 26篇 |
2015年 | 13篇 |
2014年 | 19篇 |
2013年 | 124篇 |
2012年 | 34篇 |
2011年 | 38篇 |
2010年 | 39篇 |
2009年 | 50篇 |
2008年 | 44篇 |
2007年 | 32篇 |
2006年 | 23篇 |
2005年 | 25篇 |
2004年 | 18篇 |
2003年 | 13篇 |
2002年 | 9篇 |
2001年 | 17篇 |
2000年 | 12篇 |
1999年 | 9篇 |
1998年 | 21篇 |
1997年 | 18篇 |
1996年 | 14篇 |
1995年 | 22篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1977年 | 17篇 |
1976年 | 12篇 |
1975年 | 10篇 |
1974年 | 8篇 |
1973年 | 8篇 |
1972年 | 5篇 |
排序方式: 共有874条查询结果,搜索用时 0 毫秒
41.
Richard E. Hammond 《Coastal management》2013,41(2):189-192
Onshore Planning for Offshore Oil—Lessons from Scotland by Pamela L. Baldwin and Malcolm F. Baldwin The Conservation Foundation, Washington, D.C., 1975 相似文献
42.
Maarten Kroesen Eric J.E. Molin Henk M.E. Miedema Henk Vos Sabine A. Janssen Bert van Wee 《Transportation Research Part D: Transport and Environment》2010,15(3):144-153
This study assesses the effects of aircraft noise on residential satisfaction, an important indicator of subjective well-being. A structural equation model is specified that estimates the relationships between objective variables, noise annoyance variables and residential satisfaction. Secondary data-analysis is used to estimate the model. The survey was conducted in 1996/1997 among the population living within a 25-km radius of Amsterdam Schiphol, the largest airport in the Netherlands. The effect of aircraft noise annoyance is found to be relatively small. In addition, the objective level of aircraft noise exposure is found to be a better predictor of residential satisfaction than its subjective counterpart. The most important determinants of residential satisfaction are found to be road traffic noise annoyance, age and neighbor noise annoyance. 相似文献
43.
E. Alcalá F. Badea Á. Martin F. Aparicio 《International Journal of Automotive Technology》2013,14(5):817-827
The analysis of structures with finite elements methods (FEM) represents a widely spread technique. For large tubular structures similar to the buses and coaches upper structures, beam type elements are utilized due to the fact that these elements provide satisfactory results at relatively reduced computational performances. However the beam type elements have a main disadvantage determined by the fact that the modeled joints have an infinite rigid behavior. This shortcoming determines a stiffer behavior of the modeled structures which translates into an error source for the structural simulations (up to 45%). To overcome this problem, a simple methodology was conceived and an alternative optimized equivalent beam model obtained. The methodology studies the behavioral characteristics of beam modeled T-junctions determining their limitations and comparing them to equivalent T-junctions modeled with shell and volume elements. This way an improved Tjunction has been obtained, in which the behavioral error was reduced to less than 5%. Furthermore the FEM obtained results were validated with real T-junctions. 相似文献
44.
Martin Stopford 《上海造船》2008,(1):8-11
以时间和船只数目来量度,航运市场正处于两百年来最兴旺的时期。中国是这段兴旺时期的最大功臣,它的贡献已被广泛讨论。经过10年的快速增长,中国对海事行业的影响正进入一个新阶段,演变中的中国经济对整个世界海事行业和中国造船业带来新挑战。 相似文献
45.
Marlies Mischinger Martin Rudigier Peter Wimmer Andreas Kerschbaumer 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2019,57(8):1108-1125
ABSTRACTThis paper describes a method to analyse and evaluate different trajectory planning methods and controller types for usage in automated vehicles. Its application is shown by using a novel trajectory planning approach considering comfort aspects (based on Rapidly Exploring Random Tree (RRT)), two different controllers to follow the planned path (cascade controller and flatness based controller) and a simulation method to obtain resulting lateral vehicle accelerations. The method is used to plan and drive a trajectory through a roundabout. It can be seen that the lateral accelerations of the controller-driven vehicle are in the range of the values used for planning. However, the results of both controllers show differences in lateral deviation and in smoothness of lateral accelerations. The simulation results are then compared to real-world test drives in the same roundabout. The measured lateral accelerations are in the same range as well but show a smoother progression than the two controller models. 相似文献
46.
This paper provides statistical evidence in support of the view, widely held in the tanker industry, that there are systematic differences in the degree of risk involved in investing in tankers of different sizes, and in operating tankers in spot and time charter markets. The industry view, broadly supported by the results of this paper, is that larger vessels are 'risker' assets than smaller vessels, and operating vessels in the time-charter market is less risky than employing them on a spot basis. The results are obtained by using a method derived from the financial economics literature, which models both the conditional mean and variance of a variable, known as GARCH modelling. Only one other paper has applied this method to the tanker market, and these results provide confirmatory support of those findings. 相似文献
47.
48.
Spatial fisheries ecology: Recent progress and future prospects 总被引:1,自引:0,他引:1
L. Ciannelli P. Fauchald K.S. Chan V.N. Agostini G.E. Dingsr 《Journal of Marine Systems》2008,71(3-4):223
We review recent progresses made in the study of fish distribution and survival over space — i.e., fisheries spatial ecology. This is achieved by first surveying the most common statistical approaches and relative challenges associated with the analysis of fisheries spatial data, loosely grouped in geostatistical and regression approaches. Then we review a selected number of case-studies implementing the discussed techniques. We conclude by proposing new areas of statistical and ecological research to further our understanding of how fish distribute and survive in space. This review serves a dual purpose by emphasizing the scientific importance of studying spatial interactions to better understand the temporal dynamics of fish abundance, and by promoting the development of new analytical and ecological approaches for the analysis of spatial data. Through our survey we cover different statistical techniques, marine ecosystems and life stages. This analytical, geographic and ontogenetic variety is also purposely selected to highlight the importance of comparative and multidisciplinary studies across diverging ecological disciplines, ecosystems and life stages. Besides having a general ecological relevance this review also bears a more applied significance, owing to the increasing need for protecting renewable marine resources along with their primary habitat. 相似文献
49.
50.
本文通过对6502站继电器采集故障原因进行分析,提出用增加复示继电器、缩短电缆长度或采集电缆单独敷设的方法,减少采集故障发生,确保列控中心识别进路信息采集的正确性。 相似文献