全文获取类型
收费全文 | 4926篇 |
免费 | 202篇 |
专业分类
公路运输 | 1377篇 |
综合类 | 1378篇 |
水路运输 | 1268篇 |
铁路运输 | 945篇 |
综合运输 | 160篇 |
出版年
2024年 | 11篇 |
2023年 | 16篇 |
2022年 | 129篇 |
2021年 | 194篇 |
2020年 | 145篇 |
2019年 | 52篇 |
2018年 | 64篇 |
2017年 | 79篇 |
2016年 | 64篇 |
2015年 | 197篇 |
2014年 | 213篇 |
2013年 | 324篇 |
2012年 | 334篇 |
2011年 | 405篇 |
2010年 | 434篇 |
2009年 | 388篇 |
2008年 | 418篇 |
2007年 | 449篇 |
2006年 | 390篇 |
2005年 | 327篇 |
2004年 | 109篇 |
2003年 | 68篇 |
2002年 | 65篇 |
2001年 | 60篇 |
2000年 | 57篇 |
1999年 | 32篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1996年 | 16篇 |
1995年 | 16篇 |
1994年 | 9篇 |
1993年 | 11篇 |
1992年 | 4篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有5128条查询结果,搜索用时 31 毫秒
201.
Wei X.Liu X.Duan Y.Feng J.Qiao N.Guo L. 《现代隧道技术》2018,(3):220-228
Water-sealed underground oil tank projects are quite different from traditional underground projects since the water-sealing conditions are very strict and the difficulties caused by the geological specificity, structural specificity and construction specificity are key factors affecting the project. In light of the significant early initial setting time and rapid temperature increase of sulphoaluminate cement-based grouting material for a large domestic water-sealed underground oil tank with pressurized cyclic grouting, a laboratory grouting simulation is conducted. It is found that the properties of the sulphoaluminate cement-based grouting material are quite different under different pressure cycles, the hydration exothermic peak time gets shorter with an increase of circulation time, the compressive strength decreases with an increase of circulation time, and the longer the circulation time the more obvious the de-crease of compressive strength. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved. 相似文献
202.
In this paper, we report the results of a stated choice experiment, which was conducted to examine truck drivers?? route choice behavior. Of particular interest are the questions (i) what is the relative importance of road accessibility considerations via-a-vis traditional factors influencing route choice behavior, (ii) what are the influences of particular personal and situational variables on the evaluation of route attributes, (iii) how sensitive are truck drivers for possible pricing policies, and (iv) is there a difference in impact if environmental concerns are framed as a bonus or as a pricing instrument. The main findings indicate that road accessibility characteristics have a substantial impact on route preferences which is of the same order of magnitude as variation in travel times. This suggests that provision of adequate travel information in itself can be an effective instrument to prevent negative externalities of good transport associated with shortest routes. Furthermore, the results indicate that truck drivers/route planners when choosing a route are relatively sensitive to road pricing schemes and rather insensitive to environmental bonuses. 相似文献
203.
This paper investigates differentiated design standards as a source of capacity additions that are more affordable and have smaller aesthetic and environmental impacts than modern expressways. We consider several tradeoffs, including narrow versus wide lanes and shoulders on an expressway of a given total width, and high-speed expressway versus lower-speed arterial. We quantify the situations in which off-peak traffic is sufficiently great to make it worthwhile to spend more on construction, or to give up some capacity, in order to provide very high off-peak speeds even if peak speeds are limited by congestion. We also consider the implications of differing accident rates. The results support expanding the range of highway designs that are considered when adding capacity to ameliorate urban road congestion. 相似文献
204.
205.
206.
207.
208.
209.
公路隧道围岩分级中存在问题的探讨 总被引:1,自引:0,他引:1
210.
列举了近十年间油船修理爆炸事故案例,分析了油船爆炸事故频发现象,进一步探讨了油船爆炸事故成因,提出了油船修理应遵循的步骤。 相似文献