全文获取类型
收费全文 | 6521篇 |
免费 | 104篇 |
专业分类
公路运输 | 1670篇 |
综合类 | 1345篇 |
水路运输 | 1985篇 |
铁路运输 | 552篇 |
综合运输 | 1073篇 |
出版年
2023年 | 26篇 |
2022年 | 85篇 |
2021年 | 95篇 |
2020年 | 64篇 |
2019年 | 54篇 |
2018年 | 428篇 |
2017年 | 362篇 |
2016年 | 370篇 |
2015年 | 93篇 |
2014年 | 181篇 |
2013年 | 509篇 |
2012年 | 328篇 |
2011年 | 511篇 |
2010年 | 522篇 |
2009年 | 355篇 |
2008年 | 465篇 |
2007年 | 412篇 |
2006年 | 259篇 |
2005年 | 253篇 |
2004年 | 134篇 |
2003年 | 148篇 |
2002年 | 73篇 |
2001年 | 80篇 |
2000年 | 87篇 |
1999年 | 40篇 |
1998年 | 48篇 |
1997年 | 60篇 |
1996年 | 53篇 |
1995年 | 64篇 |
1994年 | 31篇 |
1993年 | 32篇 |
1992年 | 24篇 |
1991年 | 16篇 |
1990年 | 31篇 |
1989年 | 21篇 |
1988年 | 20篇 |
1987年 | 16篇 |
1986年 | 16篇 |
1985年 | 24篇 |
1984年 | 20篇 |
1983年 | 18篇 |
1982年 | 26篇 |
1981年 | 29篇 |
1980年 | 22篇 |
1979年 | 34篇 |
1978年 | 13篇 |
1977年 | 21篇 |
1976年 | 10篇 |
1975年 | 13篇 |
1974年 | 11篇 |
排序方式: 共有6625条查询结果,搜索用时 9 毫秒
31.
This paper presents the results of an investigation into temporal determinants of maritime accidents based on a data-set obtained from the proceedings of formal inquiries in the former German Democratic Republic (GDR). The results show that there is no statistically significant outcome between the probability for an accident and the time of watch. Thus the results do not confirm previous studies, which reported significant time of day effects.The outcome of this study indicates that marine inquiries can provide useful data for an analysis of underlying causes of maritime accidents. It is suggested that accident inquiries should be extended into the area of watch systems employed and should record the hours of work and of rest of the officers on the watch involved in a maritime accident. 相似文献
32.
C. Julian Parker 《WMU Journal of Maritime Affairs》2003,2(2):99-113
This article is in three parts. The first covers the historical development of qualifying associations. The second covers the particular role of maritime institutions that include The Royal Institution of Naval Architects, The Institute of Marine Engineering Science and Technology and The Nautical Institute. The third and final section considers the future for maritime professional associations in the context of international shipping. 相似文献
33.
龙屯路立交钢管混凝土简支系杆拱桥主桥设计研究 总被引:4,自引:3,他引:1
柳州龙屯路立交桥主桥结构形式为跨径92.5 m下承式简支系杆钢管混凝土拱桥,通过分析结构体系的温度敏感性,本桥接近同类结构形式的极限跨度。主要介绍该桥的结构设计和结构静力计算情况,并对结构的合理拱轴系数进行分析研究。 相似文献
34.
35.
A linear theory for the physical fields in the water column under the action of large amplitude internal lee waves at the main sill of the Strait of Gibraltar is developed. The procedure is a combination of the perturbation and normal modes methods in order to study steady resonant conditions. The lowest order linear approach of the methodology resumes the Taylor–Goldstein equation, which can reconstruct the main features of the observed fields but the high order approach gives the finest structure and sometimes the largest contributions. The role of the non-linear terms is investigated up to the second order taking into account the non-linear interactions between modes, leading to an effective reconstruction of the whole water column for the velocity field. 相似文献
36.
37.
38.
Y. Hattori K. Asano N. Iwama T. Shigematsu 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1995,24(4):299-311
This report describes a decelerating driver-model expressed by driving mode transition in car-following situations. The assumptions for constructing the model are that decelerating strategy of a driver is classified into several simple driving modes and that a driver changs his driving modes based on his perceptible characteristics and experiential rules. Deceleration action is divided into three states; following, standing and braking, which are applied to the model. The model has two paths for driver's decelerating action, one of which is selected by the driver based on the perceptible characteristics and experiential rules. The suitability of the model has been experimentally verified. 相似文献
39.
测绘技术是随着科技的发展而不断进步的,促进了测绘技术的一次次革命,到今天功能齐全的网络测绘技术,无不显示了科技对测绘技术的影响力。本文主要讨论了高科技测绘技术的特点,并在此基础上介绍了几个当今比较流行的信息测绘技术,然后讨论了信息技术带给测绘工业体制上改革,以及最终信息化测绘的发展方向。 相似文献
40.
The work described was undertaken as part of the CASSIOPE project in the EC DRIVE programme. A range of fare collection procedures in public transport is described, and the importance of these for data collection by operators is stressed. It is suggested that such data management could be standardized and to this end four case studies were carried out in different European cities. Data models were built for each city, and these models are merged into a preliminary version of a generalized model. The need and uses for such a fare collection data model is explained. 相似文献