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   156篇
  免费   1篇
公路运输   24篇
综合类   25篇
水路运输   29篇
铁路运输   3篇
综合运输   76篇
  2022年   1篇
  2021年   4篇
  2020年   1篇
  2019年   3篇
  2018年   10篇
  2017年   4篇
  2016年   8篇
  2015年   2篇
  2014年   4篇
  2013年   20篇
  2012年   7篇
  2011年   8篇
  2010年   7篇
  2009年   14篇
  2008年   18篇
  2007年   8篇
  2006年   4篇
  2005年   4篇
  2004年   2篇
  2003年   1篇
  2002年   3篇
  2000年   4篇
  1999年   1篇
  1998年   1篇
  1995年   2篇
  1994年   1篇
  1993年   4篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1981年   1篇
  1978年   1篇
  1977年   1篇
  1974年   2篇
排序方式: 共有157条查询结果,搜索用时 234 毫秒
131.
康明斯上半年业绩再创历史新高 康明斯公司日前发布二季度财务公报,销售额和利润均创历史最高纪录,美国以外海外市场的迅猛增势有效抵御了美国经济疲软带来的负面影响。本季度国际业务额占康日月斯全球销售的比重持续攀升,从上季度的57%增至二季度的61%,2007年海外业务的比重则是54%.显示康明斯多元化的全球市场战略继续发挥至关重要的作用。  相似文献   
132.
南非商用车市场2014上半年的销售让人印象深刻,但是,在劳工运动对汽车制造商持续产生影响的形势下,我们不禁要问,接下来的市场还能迎来上升吗?本文主要分析了2014年第2季度(4-6月)车辆总质量(gross vehicle mass,GVM)为3.5 t以上的南非商用车市场情况,以季度为时间单位是为了减少一些短期内市场行为的影响,比如,大批量交货、推出新产品、旧产品系列淘汰,等等.  相似文献   
133.
Defining and understanding trip chaining behaviour   总被引:4,自引:0,他引:4  
Trip chaining is a phenomenon that we know exists but rarely investigate. This could be attributed to either the difficulty in defining trip chains, extracting such information from travel diary surveys, the difficulty in analysing all the possible trip chain types, or all of the above. Household travel diary surveys provide a wealth of information on the travel patterns of individuals and households. Since such surveys collect all information related to travel undertaken, in theory it should be possible to extract trip-chaining characteristics of travel from them. Due to the difficulty in establishing and analysing all of the possible trip chain types, the majority of research on trip chaining has appeared to focus on work travel only. However, work related travel in many cities does not represent the majority of activities undertaken and, for some age groups, does not represent any travel at all. This paper begins by reviewing existing research in the field of trip chaining. In particular, investigations into the definitions of trip chaining, the defined typologies of trip chains and the research questions that have been addressed are explored. This review of previous research into trip chaining facilitates the following tasks: the identification of the most useful questions to be addressed by this research; defining trip chaining and associated typologies and defining data structures to extract trip chaining information from the household travel surveys conducted in metropolitan Adelaide, South Australia. The definition and typology developed in our research was then used to extract trip-chaining information from the household travel diary survey (MAHTS99) conducted in Adelaide in 1999. The extracted trip chaining information was then used to investigate trip-chaining behaviour by households. The paper reports the results of this analysis and concludes with a summary of the findings and recommendations for further investigations.  相似文献   
134.
This paper presents results from a plug-in hybrid vehicle drive share program involving retrofitted hybrid electric vehicles. A potential for high fuel efficiency is indicated, however, the average fuel efficiency was only marginally better than conventional hybrid vehicles. This is due to the majority of vehicle miles traveled occurring on trips outside the “all electric” range and very short trips where fuel consumption is dominated by emissions control strategies. The work also considers the availability of the battery for vehicle to grid services and finds that there are a large number of trips in the afternoon period, typically when electrical demand is at a peak. Vehicle charging activity also tended towards daytime activity, contrary to the oft-assumed off-peak charging pattern.  相似文献   
135.
The paper develops a methodology for assessing the relative risk levels in moving hazardous materials by various transport modes. Transportation Risk ANalysis tool for hazardous Substances (TRANS) divides routes into smaller segments using multi-criteria analysis and likelihood scores of accidents in which dangerous cargoes are involved possibly causing fatalities. The consequences of accident scenarios are calculated in terms of the number of people within 1% of the lethal distance from the accident centre. This provides a user-friendly, semi-quantitative risk analysis tool. The generic method allows for comparing the risk levels of the segments of routes used in the transportation of hazardous goods.  相似文献   
136.
In this paper, we measure the relations between stated and revealed car preferences and the use of information sources in the car-purchasing process, based on a survey of households in the Netherlands. The analysis showed that attitudinal and behavioral constructs are found for ‘environmental’, ‘performance’, and ‘convenience’ preferences, but that there is a ‘gap’ between attitude and behavior. The results show that people with a positive environmental attitude who also show environmentally friendly behavior have more involvement with cars than people who do not translate their environmental attitude into the corresponding behavior. This leads to the idea that not only environmental knowledge but also involvement with cars is a prerequisite for buying an environmentally friendly car.  相似文献   
137.
介绍了一种经久耐用的可以减小汽油机摩擦功和CO2排放的新型抗磨损低摩擦的活塞裙部涂层。适应了当前高强化发动机和节能减排的市场需求。  相似文献   
138.
This paper introduces a vehicle transaction timing model which is conditional on household residential and job relocation timings. Further, the household residential location and members’ job relocation timing decisions are jointly estimated. Some researchers have modeled the household vehicle ownership decision jointly with other household decisions like vehicle type choice or VMT; however, these models were basically static and changes in household taste over time has been ignored in nearly all of these models. The proposed model is a dynamic joint model in which the effects of land-use, economy and disaggregate travel activity attributes on the major household decisions; residential location and members’ job relocation timing decisions for wife and husband of the household, are estimated. Each of these models is estimated using both the Weibull and log-logistic baseline hazard functions to assess the usefulness of a non-monotonic rather than monotonic baseline hazard function. The last three waves of the Puget Sound Panel Survey data and land-use, transportation, and built environment variables from the Seattle Metropolitan Area are used in this study as these waves include useful explanatory variables like household tenure that were not included in the previous waves.  相似文献   
139.
This research concerns the design of a powertrain system for a plug-in parallel diesel hybrid electric bus equipped with a continuously variable transmission (CVT) and presents a new design paradigm for the plug-in hybrid electric bus (HEB). The criteria and method for selecting and sizing powertrain components equipped in the plug-in HEB are presented. The plug-in HEB is designed to overcome the vulnerable limitations of driving range and performance of a purely electric vehicle (EV), and it is also designed to improve the fuel economy and exhaust emissions of conventional buses and conventional HEBs. Optimization of the control strategy for the complicated and interconnected propulsion system in the plug-in parallel HEB is one of the most significant factors for achieving higher fuel economy and lower exhaust emissions in the hybrid electric vehicle (HEV). In this research, the proposed control strategy was simulated to prove its validity using the ADVISOR (advanced vehicle simulator) analysis simulation tool.  相似文献   
140.
A long run multioutput cost function for the infrastructure services of Spanish ports is estimated using 286 observations on 26 ports during 11 years. Cargo specific marginal costs and the degree of economies of scale and scope are calculated up to a port level. Results show that liquid bulk and non-containerised general cargo present the lowest and largest marginal cost, respectively. Increasing returns to scale are present in general and for each and every port. A scope analysis indicates that port specialisation is not appropriate from the viewpoint of infrastructure.  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