全文获取类型
收费全文 | 1392篇 |
免费 | 72篇 |
专业分类
公路运输 | 329篇 |
综合类 | 470篇 |
水路运输 | 334篇 |
铁路运输 | 228篇 |
综合运输 | 103篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 35篇 |
2021年 | 50篇 |
2020年 | 38篇 |
2019年 | 16篇 |
2018年 | 15篇 |
2017年 | 33篇 |
2016年 | 35篇 |
2015年 | 44篇 |
2014年 | 68篇 |
2013年 | 75篇 |
2012年 | 78篇 |
2011年 | 112篇 |
2010年 | 126篇 |
2009年 | 116篇 |
2008年 | 119篇 |
2007年 | 136篇 |
2006年 | 125篇 |
2005年 | 77篇 |
2004年 | 30篇 |
2003年 | 27篇 |
2002年 | 18篇 |
2001年 | 18篇 |
2000年 | 15篇 |
1999年 | 13篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1988年 | 1篇 |
1987年 | 2篇 |
排序方式: 共有1464条查询结果,搜索用时 9 毫秒
41.
42.
43.
44.
文章结合南宁大桥主桥承台大体积混凝土施工实例,分析了大体积混凝土产生裂缝的原因,并从承台大体积混凝土施工方案、材料选择、配合比设计、现场浇筑质量控制等方面,介绍了保证承台大体积混凝土施工质量的控制措施以及取得的效果,对类似工程有一定的借鉴作用。 相似文献
45.
Safety modeling for two‐way left‐turn lanes and a procedure to identify two‐way left‐turn lane segments with safety concerns 下载免费PDF全文
In the past, two‐way left‐turn lane (TWLTL) median treatments have been frequently used in Florida to inexpensively improve traffic and safety performances. In order to identify factors that may have significant impacts on safety operations in TWLTL sections and to identify TWLTL locations that present existing and future safety concerns, a research project was carried out and results are summarized in the paper. In the research, a three‐year crash history database with crashes and section characteristics from a total of 1688 TWLTL sections all over Florida was developed and used. A negative binomial regression model was developed to determine the statistical relationship between the number of crashes per mile per year and several variables such as traffic volume, access density, posted speed, and number of lanes. In regard to the methodology, in order to identify locations with safety concerns, several steps are needed: development of real crash data distribution, determination of statistical distribution models that better represent the actual crash data, determination of percentile values for the average number of crashes, estimation of crash rates for sections with the same characteristics, estimation of critical values for the variables corresponding to the percentile values for average number of crashes, calculation of tables of critical average annual daily traffic values, and generation of a list of TWLTL locations with critical safety concerns. Results presented in the paper have been used in real applications. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
46.
A three-stage approach, i.e., factor-cluster-multi-group Structural Equation Modeling (SEM), is designed to explore the commonalities and diversities with respect to relationships between socio-demographic characteristics and time-use patterns across different segments. Factor-cluster analysis is conducted to extract meaningful factors from attitudinal statements, and then group the sample population into three segments, each with a unique combination of mode preferences for public transit, private car, and motorcycle. By virtue of multi-group SEM, the relationships between socio-demographics and time allocated to activities and travel are found to be significantly different across segments. This study highlights the importance of latent psychological factors in segmentation. For policy implication, specific population with unique psychological features must be targeted in order to efficiently and effectively design and implement transport measures. 相似文献
47.
48.
Transportation - Electronic Toll Collection (ETC) systems are based on tags, on-board units associated to personal bank accounts, used for paying tolls electronically. Despite the benefits... 相似文献
49.
文章基于某跨越既有线大跨径预应力混凝土连续箱梁悬臂施工阶段划分情况,利用Midas/Civil程序软件,建立了三维有限元实体模型,对连续梁桥各施工阶段的主梁内力、应力及挠度进行了仿真模拟分析。结果表明,该有限元分析方法能精确模拟结构的实际受力情况。 相似文献
50.
This paper examines some key aspects of a charging system for promoting railway transport, including charges reflecting a clear relationship with costs (transparency) and charges reflecting the quality of the infrastructure manager's service. Train running charges recover track-related costs and can help to develop a charging system that meets these requirements. To orient train running charges to the market, a method for processing track maintenance and renewal costs is proposed whereby the quality of the service provided by an infrastructure is measured according to its utility to the railway undertaking. To achieve transparency, a single indicator is used for cost planning and the subsequent levying of costs on railway undertakings. The paper includes an example of how proposed train running charges would be calculated according to data from 14 European countries. The example shows that short-distance trains generate the lowest maintenance and renewal costs, followed by long-distance trains and freight trains. 相似文献