全文获取类型
收费全文 | 1721篇 |
免费 | 134篇 |
专业分类
公路运输 | 566篇 |
综合类 | 604篇 |
水路运输 | 315篇 |
铁路运输 | 293篇 |
综合运输 | 77篇 |
出版年
2024年 | 4篇 |
2023年 | 19篇 |
2022年 | 36篇 |
2021年 | 47篇 |
2020年 | 57篇 |
2019年 | 51篇 |
2018年 | 41篇 |
2017年 | 52篇 |
2016年 | 55篇 |
2015年 | 48篇 |
2014年 | 108篇 |
2013年 | 80篇 |
2012年 | 126篇 |
2011年 | 135篇 |
2010年 | 146篇 |
2009年 | 140篇 |
2008年 | 117篇 |
2007年 | 149篇 |
2006年 | 124篇 |
2005年 | 81篇 |
2004年 | 46篇 |
2003年 | 46篇 |
2002年 | 21篇 |
2001年 | 19篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 7篇 |
1997年 | 11篇 |
1996年 | 12篇 |
1995年 | 5篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1985年 | 1篇 |
排序方式: 共有1855条查询结果,搜索用时 15 毫秒
51.
针对黄骅港区饱和密实粉土,通过三轴剪切试验以及原型耙齿切削试验,研究饱和密实粉土剪胀特性及其对耙齿切削阻力的影响。三轴试验结果表明,黄骅地区饱和密实粉土在剪切过程中表现为应变软化性状,偏应力峰值与围压之间基本呈线性关系。在剪切过程中,土体先剪缩后剪胀,随着围压的增大,剪缩性状体现得越来越明显,应力应变性状可划分为4个不同阶段。原型耙齿切削试验结果表明,饱和土较非饱和土切削阻力增长得更快;饱和土切削阻力最大值为非饱和土切削阻力最大值的2.7~3.3倍;对于饱和土,切削阻力达到稳定值后,其波动幅度较非饱和土要大。上述试验结果均表明,土的剪胀性对于耙齿切削阻力的影响十分显著,须采取相应的措施来降低土的剪胀性对于耙齿切削阻力的影响。 相似文献
52.
基于铝合金模板在唐山港曹妃甸港区联想控股通用件杂货泊位二期工程中的应用,对其应用特点、施工工艺及应用效果进行分析。认为铝合金模板是一种低耗、环保、经济实用的绿色模板,在国内港口工程中具有广阔的推广前景。 相似文献
53.
54.
This paper examines the activity engagement, sequencing and timing of activities for student, faculty and staff commuter groups at the largest university in the Maritime Provinces of Canada. The daily activity patterns of all university community groups are modeled using the classification and regression tree classifier algorithm. The data used for this study are derived from the Environmentally Aware Travel Diary Survey (EnACT) conducted in spring 2016 at Dalhousie University, Nova Scotia. Results show that there are significant differences in activity and travel behavior between university population segments and the general population in the region, and between campus groups. For example, students participate in more recreation activities compared to faculty and staff. They also take more trips to and from campus, and are more flexible in their scheduling of trips. The insights gained from this study will provide helpful information for promoting sustainability across university campuses, and for development of campus-based travel demand management strategies. 相似文献
55.
56.
Carsharing is an innovative travel alternative that has recently experienced considerable growth and become part of sustainable transportation initiatives. Although carsharing is becoming increasingly a popular alternative transportation mode in North America, it is still an under‐researched area. Current research is aimed at better understanding of the behavior of carsharing users. For every member, a two‐stage approach microsimulates the probability of being active in any month using a binary probit model and given that a particular member is active during a month, the probability of that member using the service multiple times using a random utility‐based model. The model is estimated using empirical data from one of the largest carsharing companies in North America. The model estimates reveal that the activity persistency of members is positively linked to previous behaviors for up to 4 months, and that the influence of previous months weakens over time. It also shows that some attributes of the traveler (gender, age, and language spoken at home) impact his or her behaviors. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
57.
Baibing Li 《Transportation Research Part B: Methodological》2012,46(1):85-99
Vehicle time headway is an important traffic parameter. It affects roadway safety, capacity, and level of service. Single inductive loop detectors are widely deployed in road networks, supplying a wealth of information on the current status of traffic flow. In this paper, we perform Bayesian analysis to online estimate average vehicle time headway using the data collected from a single inductive loop detector. We consider three different scenarios, i.e. light, congested, and disturbed traffic conditions, and have developed a set of unified recursive estimation equations that can be applied to all three scenarios. The computational overhead of updating the estimate is kept to a minimum. The developed recursive method provides an efficient way for the online monitoring of roadway safety and level of service. The method is illustrated using a simulation study and real traffic data. 相似文献
58.
提出了对应于角闪烁时域统计性模型中一类子模型的特定生成算法,并在时域统计信号上增加了相应的频域特性。通过仿真实验得到的时域统计图形和频域功率谱图形充分证实了算法的正确性。 相似文献
59.
60.
高永强 《广东交通职业技术学院学报》2007,6(4):90-92
文中探讨和讲述了根据高职教育的教学特点和市场需求,以就业为导向开发汽车运用技术专业的专业课程。 相似文献