全文获取类型
收费全文 | 2396篇 |
免费 | 43篇 |
专业分类
公路运输 | 744篇 |
综合类 | 333篇 |
水路运输 | 704篇 |
铁路运输 | 286篇 |
综合运输 | 372篇 |
出版年
2023年 | 7篇 |
2022年 | 43篇 |
2021年 | 52篇 |
2020年 | 29篇 |
2019年 | 19篇 |
2018年 | 47篇 |
2017年 | 47篇 |
2016年 | 41篇 |
2015年 | 37篇 |
2014年 | 91篇 |
2013年 | 243篇 |
2012年 | 164篇 |
2011年 | 171篇 |
2010年 | 172篇 |
2009年 | 153篇 |
2008年 | 166篇 |
2007年 | 161篇 |
2006年 | 147篇 |
2005年 | 118篇 |
2004年 | 37篇 |
2003年 | 43篇 |
2002年 | 40篇 |
2001年 | 41篇 |
2000年 | 52篇 |
1999年 | 21篇 |
1998年 | 30篇 |
1997年 | 26篇 |
1996年 | 27篇 |
1995年 | 16篇 |
1994年 | 12篇 |
1993年 | 11篇 |
1992年 | 20篇 |
1991年 | 15篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1982年 | 6篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1973年 | 5篇 |
1972年 | 3篇 |
排序方式: 共有2439条查询结果,搜索用时 484 毫秒
101.
102.
Margarida C. Coelho Marco B. Luzia 《Transportation Research Part D: Transport and Environment》2010,15(8):443-450
This paper analyzes the energetic performance of the hybrid Lexus RX 400h, through on-board measurements. Several speed profiles were analyzed, for three driving types, successive stop and go cycles, three speed profiles, crossing an electronic toll collection booth, and a roundabout. In stop and go situations the internal combustion engine did not work (the torque needed to impulse the vehicle in the stop and go situations was only supported by the electric engines), as well as in the situations of constant low speeds (50 or 60 km h?1). The auxiliary support given by the electric engines in the accelerations, as well as the importance of the energy regeneration system on the batteries’ load recovery is also demonstrated. When compared with similar conventional vehicles, the Lexus RX 400h has lower combined energy consumption between 1.2% and 60%. 相似文献
103.
104.
Chia-Juch Chang Robert D. Miles Kumares C. Sinha 《Transportation Research Part B: Methodological》1981,15(4):227-238
A regional railroad network is presented to evaluate the system's response to increased coal traffic. An optimal, multimodal, coal-shipping pattern is developed for the study region to minimize total costs and to efficiently use the existing network. A two-stage, general model allocates resources among demands and then assigns flows to the network according to efficiency criteria. The model is sufficiently general to permit modification for specific needs, assumptions and data. Government agencies and industries can apply the model in resource allocation decisions and transportation policy analysis. 相似文献
105.
从六潜高速公路所处独特地理位置和水文条件出发,分析了水损害的成因,提出了减少水损害的预防措施,从而将水损害初期危害降到最低,使其更好地发挥在大别山区的交通枢纽作用。 相似文献
106.
Joanne Ellis Björn Forsman Susann Gehl Uwe Langbecker Kurt Riedel Pierre C. Sames 《WMU Journal of Maritime Affairs》2008,7(1):133-149
Commercial shipping of containerized goods involves certain risks for human safety and environment. In order to actively manage these risks, they must be identified, analyzed, modeled, and quantified. This requires a systematical analysis of design and operation of container vessels. Within the EU-funded research project SAFEDOR, a Formal Safety Assessment has been applied to establish the current safety level of generic container ships and to identify potential cost-effective risk control options. This paper describes a structured approach to develop the underlying high-level risk model. It is structured as risk contribution tree consisting of a series of fault trees and event trees for the major accident categories. Statistical analysis of casualty data is used to estimate the probability of occurrence. Finally, the summation overall individual risk contributions yields the current risk pro file for the operation of container vessels is presented as FN-curve. 相似文献
107.
为了提高后浇带模板施工质量,解决拆模难度大等问题,提出一种新型、免拆除的快易收口网后浇带施工模板.从施工工艺、技术、造价等方面对比传统模板进行综合分析,论证快易收口网后浇带模板的优越性,归纳总结其施工质量控制关键点,并成功应用于某大型水利枢纽工程建设中,使得该工程抽检的6个后浇带部位蜂窝个数、平面位置偏差、混凝土表面高差、后浇带强度、表面观测等指标均满足设计要求.为该新型模板工程施工技术发展提供依据和基础. 相似文献
108.
低动力作用货车转向架动力性能的研究 总被引:2,自引:0,他引:2
沈志云 《西南交通大学学报》1991,(1)
本文探讨低动力作用货车转向架的原理及其动力性能的计算和评估方法。首先定义9项指标,作为衡量车辆对轨道动力作用的标准。然后研究这些指标的诸因素。在此基础上总结出实现低动力作用的基本途径。本文还应用这些研究成果,提出4种低动力作用货车转向架的设计方案,并通过数值计算,同国内、外主型货车转向架对比,从而论证其在我国铁路采用的可行性。 相似文献
109.
围绕DP2和DP3动力定位船舶的设计、建造、检验及运营管理,介绍了FMEA在整个周期中所起的重要作用,结合各船级社和IMO规范要求,详述了FMEA的概念,分析和试验的方法、步骤和流程,并对单点故障、冗余等相关概念作了具体描述;最后简述了船舶DP操作手册的基本概念。 相似文献
110.
China, Japan, and the European Union use weight-based fuel economy standards, whereas the US Department of Transportation favors footprint-based standards. In this paper we offer a way of reconciling these approaches. Weight-based standards tend to focus regulatory incentives on technology rather than downsizing, but they provide no incentive for weight reduction. Footprint-based standards, by contrast, motivate vehicle manufacturers to reduce weight without reducing footprint, but only to the extent that they are also motivated to increase footprint without increasing weight. Neither approach discriminates between beneficial and detrimental weight-changing strategies. However, the tradeoffs between weight and footprint can be circumvented by employing a weight-based standard, which does not create weight-changing incentives, in combination with complementary regulatory measures that would be focused specifically and exclusively on motivating beneficial weight reduction strategies. 相似文献