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   536篇
  免费   14篇
公路运输   80篇
综合类   148篇
水路运输   94篇
铁路运输   22篇
综合运输   206篇
  2024年   2篇
  2023年   4篇
  2022年   6篇
  2021年   4篇
  2020年   9篇
  2019年   3篇
  2018年   18篇
  2017年   22篇
  2016年   26篇
  2015年   36篇
  2014年   29篇
  2013年   59篇
  2012年   40篇
  2011年   37篇
  2010年   15篇
  2009年   20篇
  2008年   27篇
  2007年   35篇
  2006年   30篇
  2005年   20篇
  2004年   16篇
  2003年   5篇
  2002年   11篇
  2001年   10篇
  2000年   12篇
  1999年   11篇
  1998年   4篇
  1997年   11篇
  1996年   3篇
  1995年   3篇
  1994年   6篇
  1993年   3篇
  1992年   1篇
  1991年   6篇
  1989年   2篇
  1988年   1篇
  1986年   3篇
排序方式: 共有550条查询结果,搜索用时 359 毫秒
131.
张伟祥  王东涛  陈斌 《船舶工程》2011,33(Z2):173-175
介绍了项目管理中质量控制思路,指出应在项目管理中贯彻全系统、全寿命的质量观,并结合军代表质量监督工作的实践,对国防军工企业型号项目管理中的质量控制工作从立项论证、工程研制、生产过程和使用维修几个阶段进行了阐述.  相似文献   
132.
工程制造和施工行业是一项复杂的工作,在执行过程中涉及许多高风险作业,安全生产和安全施工工作在其中占有非常重要的位置。我们在工程项目管理中的安全目标是零伤害。  相似文献   
133.
Agent-based approaches to simulating long-term location and mobility decisions and short-term activity and travel decisions of households and individuals are receiving increasing attention in land-use and transportation interaction (LUTI) models to predict land-use changes and travel behaviour in mutual interaction. Social interactions between households and between individuals potentially have an influence on a wide range of the long-term and short-term choices involved in these systems. In this paper we identify the areas in which social interactions play a role and address the question how these influences can be modelled in the context of agent-based LUTI models. We distinguish impacts on activity participation (joint activity participation, support-and-help activities) and impacts on decision making (information exchange, social adaptation of preferences and aspirations) as the two main areas of social influence. A prototype of a LUTI model is proposed that accounts for impacts of the social network on longer-term mobility decision making through information exchange and social adaptation of preferences and aspirations. The model is demonstrated in a numerical simulation.  相似文献   
134.
135.
李强  王蓉蓉  路维  胡江碧 《公路》2012,(5):223-229
以平原区双车道公路交通事故资料为基础,分析了道路平曲线和纵断面线形及交叉口等因素与交通事故的关系,将分析结论和国外研究结果相对比,得出我国平原区双车道公路交通条件与交通安全的关系,并建立交通安全性预测模型,对提升我国双车道公路安全性具有重要的意义。  相似文献   
136.
Land border crossings in North America, such as those between Canada and U.S.A., are expected to experience severe imbalance of travel demand and capacity of processors. During peak travel periods, this is already the case at high traffic locations. The land border crossing authorities have to address problems of congestion, national security and environmental impacts in the operation of the existing systems and to continue to address these problems as a part of infrastructure expansion plans. There is a need to adapt the crossing system management in order to accommodate efficiency and productivity‐oriented priority crossing measures. From a methodological perspective, it is a challenge to evaluate the role of priority crossing measures within the complex border crossing system. This paper reports research on modelling priority crossing initiatives. A microsimulation approach was used to model and analyse integrated processors of the Peace Bridge crossing system between Fort Erie (Ontario) and Buffalo (New York) under different scenarios of travel demand, customs processing times, priority crossing and queue jump lanes for automobile and truck traffic. Findings show the extent to which a border crossing system with priority crossing and queue jump lanes is more efficient and productive than one without these innovations. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
137.
In this paper we examine two questions; what is it that makes some cases of airlines within airlines apparently successful while in many other cases it is just the opposite? And second, why would a carrier attempt such a strategy, is there a common set of circumstances or is each case unique? In the US, Canada and Europe a number of legacy carriers have sought to respond to LCC entry by creating an LCC within the legacy carriers; most have failed but some have succeeded, most notably in Australia and Germany. We first examine the evolution of the LCC business model and illustrate the different forms it takes today. Following this we provide a discussion of the underlying sources of cost advantage of the LCC and assess which sources are sustainable in the longer term. Finally we examine the conditions under which these apparent successes have occurred and look for common threads. We find market dominance, judicious network planning and co-ordination are necessary conditions for success.  相似文献   
138.
导管架的浮心浮力计算可以归结于圆柱体与水平面的求交计算。但是圆柱体连接节点与水平面的求交计算很难使用解析方法。本文提出将导管架模型分解为四面体单元,分析每个四面体单元与水平面的相对关系,从而计算得到其浮力和浮心,最终汇总得到整个导管架的浮力浮心。  相似文献   
139.
Vehicle headway distribution models are widely used in traffic engineering fields, since they reflect the fundamental uncertainty in drivers' car-following maneuvers and meanwhile provide a concise way to describe the stochastic feature of traffic flows. This paper presents a systematic review of vehicle headway distribution studies in the last few decades. Since it is impossible to enumerate the merits and drawbacks of all of existing distribution models, we emphasize four advances of headway distribution modeling in this paper. First, we highlight the chronicle of key assumptions on the existing distribution models and explain why this evolution occurs. Second, we show that departure headways measured for interrupted flows on urban streets and headways measured for uninterrupted flows on freeways have common features and can be simulated by a unified microscopic car-following model. The interesting finding helps gather two kinds of headway distribution models under one umbrella. Third, we review different approaches that aim to link microscopic car-following models and mesoscopic vehicle headway distribution models. Fourth, we show that both the point scattering on the density-flow plot and the shape of traffic flow breakdown curve implicitly depend on the vehicular headway distribution. These findings reveal pervasive connections between macroscopic traffic flow models and mesoscopic headway distribution. All these new insights bring new vigor into vehicle headway studies and open research frontiers in this field.  相似文献   
140.
考虑总人口是非常数的SIRS传染病模型,在不考虑空间扩散和考虑空间扩散两种情形时,分别构建了Liapunov函数并讨论了其模型的常数平衡点的稳定性.  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