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   2576篇
  免费   119篇
公路运输   407篇
综合类   992篇
水路运输   424篇
铁路运输   354篇
综合运输   518篇
  2024年   10篇
  2023年   7篇
  2022年   25篇
  2021年   56篇
  2020年   81篇
  2019年   50篇
  2018年   77篇
  2017年   69篇
  2016年   101篇
  2015年   121篇
  2014年   208篇
  2013年   271篇
  2012年   174篇
  2011年   216篇
  2010年   207篇
  2009年   165篇
  2008年   179篇
  2007年   167篇
  2006年   160篇
  2005年   88篇
  2004年   64篇
  2003年   55篇
  2002年   34篇
  2001年   38篇
  2000年   15篇
  1999年   7篇
  1998年   4篇
  1997年   7篇
  1996年   7篇
  1995年   5篇
  1994年   5篇
  1993年   8篇
  1992年   4篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1986年   1篇
排序方式: 共有2695条查询结果,搜索用时 750 毫秒
271.
Using photographs, this paper explores the gendered link between transport and the urban environment. It becomes apparent that moving around in urban spaces is an experience which is or can be fundamentally different for women and men. From pictures I conclude that a historical analysis of gender and urban transport ought to be a straightforward task to undertake: women are clearly visible in the visual record of the transport environment. However, a look at the historiography shows that research on gendering the city mostly deals with workplaces, women’s employment, class and race segregation in urban areas, welfare programmes specially designed to helped women, urban housing and marginalisation of women, housewives, healthcare, homeless women and politics. Gender and transport is hardly to be found: how women move and moved through urban space has not received sustained attention. Further, the main body of scholarly texts lacks in historical concern, stemming from such diverse disciplines as sociology, geography, economic and political sciences, women’s studies and planning.  相似文献   
272.
当前地铁线路各牵引所变流器独立运行,无法实现实时信息交互、精准调整和协调控制.为解决这一问题,提出基于GOOSE通信的地铁多变流器智能优化控制方法.基于GOOSE通信网络搭建多变流器分层控制结构,以系统网损最小和钢轨电位幅值最小为目标,提出基于NSGA-Ⅱ算法的多变流器双目标优化控制算法.搭建地铁牵引供电系统动态潮流仿...  相似文献   
273.
按照长三角地区城际铁路网规划,盐城市铁路将有连盐铁路、徐宿淮盐铁路、盐海铁路引入,地区铁路路网结构发生了较大变化,应对地区铁路总图规划作出修改.通过充分分析盐城市经济现状和发展趋势,对盐城的客货运量进行全面调查,在充分研究地方及过境客货运需求趋势的基础上对盐城市铁路进行研究规划.根据盐城地区引入铁路的特点,对线网格局进行分析,研究盐城市铁路客运系统布局.  相似文献   
274.
ABSTRACT

The impacts of air transport on the economy arise both directly, via activity in the aviation sector; and indirectly, via increased spending and wider economic benefits associated with improved access to resources, markets, technology and economic mass. Economic activity, in turn, supports and generates demand for air transport. Despite its potential importance, the reciprocal nature of the causal relationship between air transport and economic performance has remained somewhat understudied. This paper provides a synthesis review of the channels the aviation sector interacts with regional economy. The review focuses on quantitative studies that contribute to the state-of-the-art understandings of the causality. We find that the reciprocal causal relationship is more likely to prevail in less developed economies. For more developed economies, only one direction of the causality is recognised, which runs from air transport to economic growth. Especially substantial is the effect of airline enplanement on service-related employment. The reverse direction of the relationship is, however, not as significant as believed in a causal sense within the developed world. Therefore, cautions need to be taken when applying income elasticities (such as the elasticity of air passenger demand with respect to GDP) in air travel demand forecasting, which implicitly assumes that economic growth causally leads to air traffic increment. Based on the fundamental links between air transport and economic growth, some typical imperfections and inefficiencies in aviation markets are discussed and promising avenues for future research are proposed.  相似文献   
275.
随着我国高铁迅速发展,高铁建设如何与城市功能空间协同发展的问题引起广泛关注。为了评价高铁与城市协同发展的效率,本文从城市协同性、高铁枢纽建设、站城距离等角度,构建高铁枢纽建设与城市功能空间协同发展效率评价指标体系。并引入DEA模型进行分析计算其效率匹配度,为城市既有高铁站与城市协同发展程度提供依据。最后以京沪高铁为案例分析了24个车站与所在城市的协同关系效率值,结果表明,北京南站、上海虹桥站等高铁枢纽发展较好,常州北站、苏州北站、天津南站等较差,尤其是天津南站的通过能力、客流量等产出指标还需要进一步加强。  相似文献   
276.
为提高席位资源利用率,研究了线性需求下我国铁路客运差别定价策略的优化模型。以收益最大化为目标,基于最优化理论和完全价格歧视策略,确定旅客群体最优细分数目以及每个旅客群体的最优票价,得出在客运淡季,铁路旅客最优细分数目为3~5个,各旅客群的最优票价由铁路客运市场细分数目决定。应用该模型为某城际高铁进行差别定价,试验结果表明,该模型可达到调节客流、增加收益的目的。  相似文献   
277.
刘洋 《船电技术》2020,(4):48-50
大型洗涤车间洗涤设备众多,洗脱机、烫平机、折叠机(展布机)、堆码机等等,种类繁多,工序复杂。本文设计的洗涤集成传输控制系统采用工业PLC控制器,通过传送装置将所有设备组合起来,实现洗涤车间布草的自动化洗涤、折叠、运转、堆放,减少洗涤车间人工工作量,提高生产效率。  相似文献   
278.
ABSTRACT

Transport network criticality analysis aims at ranking transport infrastructure elements based on their contribution to the performance of the overall infrastructure network. Despite the wide variety of transport network criticality metrics, little guidance is available on selecting metrics that are fit for the specific purpose of a study. To address this gap, this study reviews, evaluates and compares seventeen criticality metrics. First, we conceptually evaluate these metrics in terms of the functionality of the transport system that the metrics try to represent (either maintaining connectivity, reducing travel cost, or improving accessibility), the underlying ethical principles (either utilitarianism or egalitarianism), and the spatial aggregation considered by the metrics (either network-wide or localised). Next, we empirically compare the metrics by calculating them for eight transport networks. We define the empirical similarity between two metrics as the degree to which they yield similar rankings of infrastructure elements. Pairs of metrics that have high empirical similarity highlight the same set of transport infrastructure elements as critical. We find that empirical similarity is partly dependent on the network’s topology. We also observe that metrics that are conceptually similar do not necessarily have high empirical similarity. Based on the insights from the conceptual and empirical comparison, we propose a five-step guideline for transport authorities and analysts to identify the set of criticality metrics to use which best aligns with the nature of their policy questions.  相似文献   
279.
针对客运专业的教学现状,在专业教学中引入了历奇教育。经过教学实践,历奇教育加深了学员间的交流,转变了学员的观念,给学员提供了展示自我的舞台,给教师提供了受教育的机会,教学效果良好。  相似文献   
280.
研究车路协同城市快速路与邻接交叉口主线分散换道和速度引导自适应控制方法. 对高饱和度入口匝道与邻接交叉口,提出主线分散换道自适应控制方法,依据合流区上游不同车道密度制定换道规则,以主线流量最大化为目标确定邻接交叉口相位相序;对出口匝道存在超长排队,提出主线速度引导自适应控制方法,依据主线上游车辆目的地确定速度引导策略,以出口匝道需求与通行能力相匹配为目标确定出口匝道关联相位优先权. 采用元胞自动机模型仿真验证,结果表明,所提方法与非协调控制、传统协调控制、车路协同交叉口自适应控制相比,区域流量分别提高17.38%、5.52%、10.06%,总时间消耗分别下降35.86%、 26.21%、17.39%.  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