全文获取类型
收费全文 | 1231篇 |
免费 | 60篇 |
专业分类
公路运输 | 428篇 |
综合类 | 318篇 |
水路运输 | 207篇 |
铁路运输 | 243篇 |
综合运输 | 95篇 |
出版年
2024年 | 7篇 |
2023年 | 8篇 |
2022年 | 24篇 |
2021年 | 37篇 |
2020年 | 54篇 |
2019年 | 30篇 |
2018年 | 22篇 |
2017年 | 20篇 |
2016年 | 16篇 |
2015年 | 28篇 |
2014年 | 77篇 |
2013年 | 72篇 |
2012年 | 105篇 |
2011年 | 113篇 |
2010年 | 89篇 |
2009年 | 85篇 |
2008年 | 87篇 |
2007年 | 110篇 |
2006年 | 108篇 |
2005年 | 50篇 |
2004年 | 46篇 |
2003年 | 33篇 |
2002年 | 17篇 |
2001年 | 16篇 |
2000年 | 12篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
排序方式: 共有1291条查询结果,搜索用时 242 毫秒
421.
盾构隧道穿越既有建筑物施工应对技术 总被引:4,自引:0,他引:4
随着近几年地下工程建设的不断发展,盾构施工技术已越来越成熟,特别是在城市轨道交通建设中更显示出其优越性。但是,对于盾构施工过程中穿越障碍物或近距离通过既有建(构)筑物的施工还缺少相应的工程实例,经验相对也较少。近年来,我国城市轨道交通建设发展迅速,但是面临着越来越复杂的周边环境和施工条件,因此研究和制定相应的施工技术和应对措施十分必要。文章针对盾构施工穿越城市内河、下穿既有隧道以及湖底施工、下穿古城墙等工程实例进行分析研究,提出了针对类似情况的应对技术措施。 相似文献
422.
在丹河特大跨石拱桥的施工模拟试验研究基础上指出 :采用分环分段砌筑施工大跨径石拱桥时 ,拱架与先期形成的拱环之间的联合作用明显 ,拱圈截面应力与施工过程密切相关 相似文献
423.
田敏 《湖北汽车工业学院学报》2001,15(2):72-75
本文通过解读《学习的革命》一书主旨 ,阐述了在知识经济时代唯有更新我们的教育和学习观念 ,学会运用科学思维去自觉地认识和掌握学习技能 ,才能真正使我国现代化人才素质教育培养有质的飞跃。 相似文献
424.
425.
施工通风是特长隧道施工组织设计中的一项重要任务,对特长隧道能否顺利建成具有关键性作用,以吕梁山特长铁路隧道5号斜井工区为例,根据长大斜井与正洞多工作面施工的特点,提出设计方案,并据此推算出施工风量布置风机,以选择合理通风方案,并针对该工区施工通风特点提出了建议。 相似文献
426.
铁路车票制票技术的研究与分析 总被引:2,自引:1,他引:1
根据我国铁路旅客运输的特点,阐述在各种可选的铁路车票制式下,车票制票技术的发展和实现方法,对它们的核心技术和使用中的优缺点进行分析,在结合铁路客运专线售票对制票机的要求基础上,提出研制适合我国铁路使用的车票制票输出设备的方案和课题. 相似文献
427.
It is known that adverse weather conditions can affect driver performance due to reduction in visibility and slippery surface conditions. Lane keeping is one of the main factors that might be affected by weather conditions. Most of the previous studies on lane keeping have investigated driver lane-keeping performance from driver inattention perspective. In addition, the majority of previous lane-keeping studies have been conducted in controlled environments such as driving simulators. Therefore, there is a lack of studies that investigate driver lane-keeping ability considering adverse weather conditions in naturalistic settings. In this study, the relationship between weather conditions and driver lane-keeping performance was investigated using the SHRP2 naturalistic driving data for 141 drivers between 19 and 89 years of age. Moreover, a threshold was introduced to differentiate lane keeping and lane changing in naturalistic driving data. Two lane-keeping models were developed using the logistic regression and multivariate adaptive regression splines (MARS) to better understand factors affecting driver lane-keeping ability considering adverse weather conditions. The results revealed that heavy rain can significantly increase the standard deviation of lane position (SDLP), which is a very widely used method for analyzing lane-keeping ability. It was also found that traffic conditions, driver age and experience, and posted speed limits have significant effects on driver lane-keeping ability. An interesting finding of this study is that drivers have a better lane-keeping ability in roadways with higher posted speed limits. The results from this study might provide better insights into understanding the complex effect of adverse weather conditions on driver behavior. 相似文献
428.
Yu Nie Xing WuJohn F. Dillenburg Peter C. Nelson 《Transportation Research Part A: Policy and Practice》2012,46(2):403-419
Reliable route guidance can be obtained by solving the reliable a priori shortest path problem, which finds paths that maximize the probability of arriving on time. The goal of this paper is to demonstrate the benefits and applicability of such route guidance using a case study. An adaptive discretization scheme is first proposed to improve the efficiency in computing convolution, a time-consuming step used in the reliable routing algorithm to obtain path travel time distributions. Methods to construct link travel time distributions from real data in the case study are then discussed. Particularly, the travel time distributions on arterial streets are estimated from linear regression models calibrated from expressway data. Numerical experiments demonstrate that optimal paths are substantially affected by the reliability requirement in rush hours, and that reliable route guidance could generate up to 5-15% of travel time savings. The study also verifies that existing algorithms can solve large-scale problems within a reasonable amount of time. 相似文献
429.
高速铁路简支箱梁架设工期研究 总被引:4,自引:2,他引:2
薛国华 《铁路工程造价管理》2006,21(4):13-16
0引言高速铁路安全、舒适、快速的运行,对路基的稳定、桥梁的刚度、轨道的平顺提出了更高的要求,因此路基、桥梁、轨道结构与一般铁路干线存在很大不同,集中体现在:路基的地基处理、基床表层级配碎石、压实密度、路桥过渡段、工后沉降要求;桥梁采用体积大、梁体重的双线箱梁;轨 相似文献