首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   107篇
  免费   0篇
公路运输   20篇
综合类   22篇
水路运输   25篇
铁路运输   18篇
综合运输   22篇
  2022年   1篇
  2021年   2篇
  2020年   4篇
  2018年   5篇
  2017年   4篇
  2016年   3篇
  2015年   4篇
  2014年   8篇
  2013年   4篇
  2012年   4篇
  2011年   7篇
  2010年   1篇
  2009年   3篇
  2008年   2篇
  2007年   10篇
  2006年   11篇
  2005年   5篇
  2004年   5篇
  2003年   6篇
  2002年   4篇
  2001年   4篇
  2000年   3篇
  1999年   1篇
  1997年   1篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
排序方式: 共有107条查询结果,搜索用时 31 毫秒
41.
舰船供电生命力测试分析   总被引:2,自引:1,他引:1  
针对目前舰船供电生命力的实际测试问题,从供电生命力的设计原则和电力系统组成两方面出发,对测试指标及测试方法进行分析研究。结合某型舰船性能鉴定工作,设计形成一整套试验方案,并进行实船测试。结果显示,该方案克服了原来的软件设计模拟评估这一缺陷,可为后续舰船性能鉴定工作提供理论和实践支撑,也可为舰船生命力评价提供一条新思路。  相似文献   
42.
马战军  白佳玉 《中国水运》2006,6(11):250-252
记名提单作为物权凭证,通过各项物权功能的发挥维系着海上货物运输合同关系的稳定并促成相关商业价值的实现。本文分析论证了记名提单作为物权凭证的权利内涵及其物权属性的具体表现;最后从司法实践角度,考察了世界主要航运国家基于肯定记名提单物权属性而在实践中坚持凭单放货原则的统一化趋势。  相似文献   
43.
The paper describes exhaust emission tests performed on a PHEV (Plug-in Hybrid Electric Vehicle) and a BEV (Battery Electric Vehicle), in which the combustion engine was used as a range extender. The measurements of the exhaust emissions were performed for CO2/fuel consumption, CO, THC and NOx. The RDE measurements were performed including the engine operating parameters and emissions analysis. This analysis shows that the engines of BEVs and PHEVs operate in a different parameter range when under actual operating conditions, which directly translates into the exhaust emission values. This is particularly the case for the emission of NOx. The investigations were carried out for two routes differentiated by the length and share of the urban and extra-urban cycles. For both routes, the emission of THC and CO were lower for the PHEV engine – HC by 69% (22 mg/km, route 1) and 6% (15 mg/km, route 2), CO by 69% (0.12 mg/km, route 1) and 80% (0.1 mg/km, route 2). For route 1, characterized by a greater share of the urban cycle, the emission of NOx was lower by 70% (2 mg/km) for the BEV engine, and (route 2) lower by 60% (8 mg/km) for the PHEV engine. Additionally, the curves of the exhaust emissions in time for individual exhaust components have been presented that indicate that in the motorway cycle the emission of THC and CO from the BEV vehicle increases significantly up to ten times compared to urban cycle.  相似文献   
44.
Transport users face complex decisions. Not only are the consequences of their choices uncertain, but they generally involve several attributes, such as time and money. Time-money tradeoffs have been studied in depth in transport economics, and research is now paying increasing attention to the role of uncertainty and information in transport decisions. This paper aims to measure the impact of uncertainty and information on multi-attribute decisions using Prospect Theory. In doing so, the study makes two contributions to transportation literature: one methodological and the other empirical. First, we propose a fast and tractable method for measuring Prospect Theory parameters that capture attitudes towards probabilities (probability weighting function) and attitudes towards losses (loss aversion). The elicitation method does not require the elicitation of the utility function. This makes it particularly suitable in complex multi-attribute decisions where the shape of the utility function is unknown. Second, we present the results of an experiment that uses the proposed method to measure, at the individual level, probability weighting in decisions involving joint time and money consequences in two decision contexts: risk (where probabilities are given) and ambiguity (where the probability distribution is unknown). An experimental setup that exposes subjects to real gains and losses for money and time has been built for this purpose. We observe inverse S-shaped probability weighting and loss aversion for risk. Probability weighting is even more pronounced in ambiguity, where subjects do not have precise information about the probability distribution. We explain how these results and the analysis of ambiguity attitudes in general can offer a better understanding of travelers’ route or transport mode choices.  相似文献   
45.
The objective of the present study is the assessment of the environmental impact of a bivalent (bi-fuel) vehicle, running either on gasoline or compressed natural gas (CNG). To that aim, a Euro 6 passenger car was tested under various real-world driving conditions. In order to cover the full range of conventional powertrains currently in the market, the tests were also repeated on a Euro 6 diesel passenger car. Both cars were driven in two routes, the first complying with the regulation limits and the second going beyond them. Carbon monoxide (CO), nitrogen oxides (NOx) and particle number (PN) emissions were recorded using a Portable Emissions Measurement System (PEMS). Apart from the aggregated emission levels, in g/km, the exact emission location along the route was also assessed. Natural gas proved beneficial for CO and PN emissions, the level of which always remained below the respective legislation limits. On the other hand, under the dynamic driving conditions with gasoline, the relevant limits were exceeded. Cold start, occurring at the beginning of the urban part, and motorway driving were identified as major contributors to total emissions, especially in gasoline mode. However, the application of natural gas was associated with a penalty in NOx emissions, which were significantly increased as compared to gasoline. Local peaks within the urban part were identified in CNG mode. In any case, the diesel vehicle was by far the highest NOx emitter.  相似文献   
46.
为研究不同认知分心等级时的驾驶人眼动行为,通过数理统计的分析方法,对实车道路试验采集的驾驶人完成不同等级认知次任务时的眼动行为特性指标进行了对比分析,定量研究了不同认知分心等级时驾驶人的眨眼、扫视及注视的变化规律。结果表明:认知次任务复杂度、眨眼频率、扫视幅度、视野广度之间显著相关。随着认知次任务难度的增加,驾驶人眨眼频率显著增加、搜索广度明显缩小、注视点分布更加集中。可见本文的研究可以为基于眼动行为的驾驶辅助系统的开发提供理论支持。  相似文献   
47.
蔡枫 《中国水运》2007,5(9):174-175
随着经济的发展,城市的建设速度越来越快,就其房地产开发投资而言,新城、旧城因其不同的地理位置、自然环境、人口环境和文化环境而各有优劣,两城区的优点和劣势也将影响和改变房地产开发的投资方面,文章将从以下几个方面进行探讨。  相似文献   
48.
在结合《物权法》中与船舶物权相关的规定的基础上,分析了《物权法》的颁行对我国船舶物权及登记制度的影响,并提出了相关立法建议。  相似文献   
49.
马克思运用辩证唯物主义和历史唯物主义的方法从“现实的人”出发,深刻揭示了人的本质。他认为人的本质是一切社会关系的总和,劳动是人的本质活动。但是马克思对人的本质的认识也是有一个过程的。目前政府在现代化建设中提出了科学发展观的理念,其中以人为本是科学发展观的核心,深刻把握马克思关于人本质的理解对于更好的领会科学发展观的内涵具有重大现实意义。  相似文献   
50.
研究悬点高度测量与放样的原理、精度分析及其观测方法。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号