全文获取类型
收费全文 | 4423篇 |
免费 | 97篇 |
专业分类
公路运输 | 1470篇 |
综合类 | 682篇 |
水路运输 | 1221篇 |
铁路运输 | 534篇 |
综合运输 | 613篇 |
出版年
2023年 | 17篇 |
2022年 | 59篇 |
2021年 | 83篇 |
2020年 | 55篇 |
2019年 | 43篇 |
2018年 | 98篇 |
2017年 | 110篇 |
2016年 | 210篇 |
2015年 | 91篇 |
2014年 | 131篇 |
2013年 | 370篇 |
2012年 | 263篇 |
2011年 | 381篇 |
2010年 | 367篇 |
2009年 | 280篇 |
2008年 | 325篇 |
2007年 | 304篇 |
2006年 | 240篇 |
2005年 | 189篇 |
2004年 | 91篇 |
2003年 | 90篇 |
2002年 | 49篇 |
2001年 | 67篇 |
2000年 | 75篇 |
1999年 | 28篇 |
1998年 | 33篇 |
1997年 | 42篇 |
1996年 | 43篇 |
1995年 | 45篇 |
1994年 | 16篇 |
1993年 | 25篇 |
1992年 | 26篇 |
1991年 | 14篇 |
1990年 | 28篇 |
1989年 | 14篇 |
1988年 | 19篇 |
1987年 | 12篇 |
1986年 | 15篇 |
1985年 | 19篇 |
1984年 | 9篇 |
1983年 | 18篇 |
1982年 | 16篇 |
1981年 | 21篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1975年 | 16篇 |
1974年 | 8篇 |
1973年 | 9篇 |
排序方式: 共有4520条查询结果,搜索用时 31 毫秒
911.
With the development of door-to-door intermodal services and the advent of just-in-time supply systems, punctual delivery of cargoes is more than ever a priority both for shippers and for shipowners. This paper is about the incidence of delay in transportation, particularly in the marine mode, and its legal and commercial consequences.
The fundamental legal obligations of marine carriers have always included delivery with dispatch. Thus the law would seem to support the commercial expectations of shippers for reliable performance. The authors discuss the nature of these obligations, investigate their adequacy under modern conditions of trade and report on a survey of Canadian shippers and consignees.
The authors conclude that there appears to be a divergence in the toleration of delay, but that few of the Canadian companies suffering unacceptable delays received, or even sought, financial compensation and none of them planned to do more. The authors speculate about their reasons for absorbing the losses incurred through unacceptable delays. The evidence from the survey is that shippers, in spite of their dissatisfaction with the resolution or outcome of incidents of unacceptable delay, are loath to seek compensation through legal means, but instead prefer to resort to a range of commercial actions. 相似文献
The fundamental legal obligations of marine carriers have always included delivery with dispatch. Thus the law would seem to support the commercial expectations of shippers for reliable performance. The authors discuss the nature of these obligations, investigate their adequacy under modern conditions of trade and report on a survey of Canadian shippers and consignees.
The authors conclude that there appears to be a divergence in the toleration of delay, but that few of the Canadian companies suffering unacceptable delays received, or even sought, financial compensation and none of them planned to do more. The authors speculate about their reasons for absorbing the losses incurred through unacceptable delays. The evidence from the survey is that shippers, in spite of their dissatisfaction with the resolution or outcome of incidents of unacceptable delay, are loath to seek compensation through legal means, but instead prefer to resort to a range of commercial actions. 相似文献
912.
153例亚急型克山病近期(起病后3个月内)病死率13.1%。猝死是最常见的死亡原因。性别、年龄及入院前病期对近期预后无明显影响。入院时病情对近期预后有明显影响,入院时以心力衰竭、严重心律失常和(或)心源性休克为主要表现者的近期病死率显著高于以单一心力衰竭为主要表现者。心电图动态观察可作为判定亚急型克山病疗效和转归的参考指标。 相似文献
913.
Data from multi-day travel or activity diaries might be biased if recording inaccuracies and tendencies for respondents to skip certain types of trips or activities increases (or decreases) from day-to-day over the diary period. One objective of the research reported here is to test for such temporal biases in a seven-day travel diary. A second objective is to calculate correction factors which can be applied to the data in the case that biases are found. The analyses were conducted using regression and analysis-of-variance techniques. The variables investigated included total trips per day, total travel time per day, and trips per day by various modes (such as walking, car driver and car passenger). Results showed that most biases per capita statistics are due to increases over time in the percentage of respondents reporting no travel at all for an entire day. However, even after accounting for this bias by measuring statistics in terms of per mobile person, there remains a decrease over time of about 3.5 percent per day in the reporting of walking trips. This appears to be the main factor in the overall bias of about one percent per day in total trips per mobile person per day. No significant differences were found among population segments in terms of the levels of their biases. 相似文献
914.
运用MIDAS/GTS三维有限元分析软件,模拟了盾构隧道动态施工对近接高架桥桩基的影响,重点分析了桩基水平位移及沉降的发展规律,为盾构安全通过提供依据。研究表明:两侧桩基水平位移在隧道范围内呈现明显"凹槽";盾构推力是影响桩基水平位移的重要因素,对沿隧道方向水平位移的影响较沿垂直隧道方向大,对桩基沉降影响较小;工程拟定袖阀管注浆加固措施将引起桩基产生附加沉降,对桩基水平位移控制无明显效果。分析结果认为,在不采取袖阀管注浆加固措施情况下,合理选取盾构推力,可完成盾构隧道对近接高架桥桩基的安全穿越。 相似文献
915.
王滨盐 《国外机车车辆工艺》2012,(6):1-4,13
国际铁路行业标准(简称IRIS)已成为优化铁路行业及其与其他相关行业增值链的国际性体系标准。介绍了IRIS体系建立的经过、与ISO 9001:2000之间的差别及通过其认证所带来的益处。 相似文献
916.
通过收集并分析相关资料,将ISO/IEC技术工作程序与我国铁道行业标准制定过程进行对比,提出可借鉴性建议。 相似文献
917.
尾矿库中伴有各种复杂的理、化、生等效应下的污染物传递过程。分析了尾矿中污染物的传输机理和涉及的层流有限速率模型、涡耗散模型、涡耗散概念模型3种化学反应模型各自的特点。结合工程实际,应用FLUENT软件对比分析了三种模型下的尾矿污染过程,模拟结果显示:Laminar Finite-Rate模型的残差曲线迭代到160步开始收敛,Eddy-Dissipation模型的残差曲线迭代到300步后仍未稳定,EDC模型的残差曲线变化较平稳迭代到120步就趋于收敛。结果表明:涡耗散模型下污染物浓度变化规律更明显;计算效率上,涡耗散概念模型比层流有限速率模型模型低;层流有限速率模型和涡耗散概念模型比涡耗散模型的计算更加准确。 相似文献
918.
宋江涛 《铁路通信信号工程技术》2012,9(6):49-51
在简要介绍TYWK驼峰控制系统结构、功能及特点的基础上,重点从系统级和工程级设计角度剖析所采取的安全性措施,随后对实践中遇到的几起典型事例进行分析,并提出相应的对策。 相似文献
919.
920.
近年来,上海轨道交通地下车站的部分通信和信号机房频繁出现温度过高现象,部分供电机房出现风管凝露滴水情况,引起设备故障。考虑到上海轨道交通各条线路车站设备管理用房通风空调系统之间存在不同的设计方式,而影响通风空调系统末端温度的因素较多,基于现场调查及测试,对地铁车站设备用房通风空调系统中存在的问题进行分析,提出了一些改善措施,指出改善设备用房末端空调的效果,需要设计、建设、运营三方共同努力。 相似文献