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   2521篇
  免费   115篇
公路运输   587篇
综合类   1074篇
水路运输   612篇
铁路运输   250篇
综合运输   113篇
  2024年   6篇
  2023年   14篇
  2022年   42篇
  2021年   50篇
  2020年   70篇
  2019年   43篇
  2018年   42篇
  2017年   57篇
  2016年   73篇
  2015年   128篇
  2014年   173篇
  2013年   136篇
  2012年   182篇
  2011年   220篇
  2010年   176篇
  2009年   178篇
  2008年   185篇
  2007年   196篇
  2006年   188篇
  2005年   147篇
  2004年   89篇
  2003年   62篇
  2002年   29篇
  2001年   39篇
  2000年   26篇
  1999年   16篇
  1998年   5篇
  1997年   5篇
  1996年   7篇
  1995年   6篇
  1994年   5篇
  1993年   5篇
  1992年   4篇
  1991年   5篇
  1990年   4篇
  1989年   7篇
  1988年   1篇
  1986年   3篇
  1985年   7篇
  1984年   5篇
排序方式: 共有2636条查询结果,搜索用时 31 毫秒
141.
The goal of a network design problem (NDP) is to make optimal decisions to achieve a certain objective such as minimizing total travel time or maximizing tolls collected in the network. A critical component to NDP is how travelers make their route choices. Researchers in transportation have adopted human decision theories to describe more accurate route choice behaviors. In this paper, we review the NDP with various route choice models: the random utility model (RUM), random regret-minimization (RRM) model, bounded rationality (BR), cumulative prospect theory (CPT), the fuzzy logic model (FLM) and dynamic learning models. Moreover, we identify challenges in applying behavioral route choice models to NDP and opportunities for future research.  相似文献   
142.
Knowledge on human behaviour in emergency is crucial to increase the safety of buildings and transportation systems. Decision making during evacuations implies different choices, of which one of the most important concerns is the escape route. The choice of a route may involve local decisions on alternative exits from an enclosed environment. This study investigates the effect of environmental (presence of smoke, emergency lighting and distance of exit) and social factors (interaction with evacuees close to the exits and with those near the decision-maker) on local exit choice. This goal is pursued using an online stated preference survey carried out making use of non-immersive virtual reality. A sample of 1503 participants is obtained and a mixed logit model is calibrated using these data. The model shows that the presence of smoke, emergency lighting, distance of exit, number of evacuees near the exits and the decision-maker and flow of evacuees through the exits significantly affect local exit choice. Moreover, the model indicates that decision making is affected by a high degree of behavioural uncertainty. Our findings support the improvement of evacuation models and the accuracy of their results, which can assist in designing and managing building and transportation systems. The main aim of this study is to enrich the understanding of how local exit choices are made and how behavioural uncertainty affects these choices.  相似文献   
143.
本文简要介绍了听力理解的实质和图式理论,探讨了图式理论在英语听力教学中的应用。指出教师要在教学中充实、激活和应用相关图式,以提高学生的听力能力。  相似文献   
144.
针对船用锅炉人因安全性分析中存在的知识不确定性,采用D-S证据理论对多专家信息进行融合并建立考虑人因的贝叶斯网络,得到节点条件概率的区间表示形式.经加权平均后代入贝叶斯网络计算,与面向对象贝叶斯网络和FTA等方法的对比显示,该方法能够更加有效地融合不同专家信息,也更为符合工程实际.  相似文献   
145.
"聚焦物流"是美军提出的一种先进物流理念,它要求在准确的地点、时间提供给联合作战各种参战人员和各类装备数量合适的后勤物资供应,它建立在以网络为基础的实时可视化信息系统之上,高效快速地连接战场指挥官和后勤供应机构,通过物流机构和程序的改革,为联合作战提供多功能的后勤保障。"聚焦物流"在历次局部战争中得到很好应用,取得良好...  相似文献   
146.
147.
148.
高速公路收费经营企业的发展战略是基于高速公路的基本特征及其未来发展趋势的前提下制定的,因此,理解高速公路的产业特征是制定高速经营发展战略的前提,同时企业战略思想的把握决定着高速公路企业经营发展战略的制定方向。  相似文献   
149.
With the progress of information and sensing technologies, estimating vehicular queue length at signalized intersections becomes feasible and has attracted considerable attention. The existing studies provided a solid theoretical foundation for the estimation; however, the studies have some restrictions or limitations more or less. This paper presents a new methodology for estimating vehicular queue length at signalized intersections using multi-source detection data under both undersaturated and oversaturated conditions. The methodology applies the shockwave theory to model queue dynamics. Using data from probe vehicles and point detectors, analytical formulations for calculating the maximum and minimum (residual) queue lengths of each cycle are developed. Ground truth data were collected from numerical experiments conducted at two intersections in Shanghai, China, to verify the proposed methodology. It is found that the methodology has mean absolute percentage errors of 17.09% and 12.28%, respectively, for maximum queue length estimation in two tests, which are reasonably effective. However, the methodology is unsatisfactory in estimating the residual queue length. Other limitations of the proposed models and algorithms are also discussed in the paper.  相似文献   
150.
The number of variables involved in the monitoring of an ecosystem can be high and often one of the first stages in the analysis is to reduce the number of variables. We describe a method developed for geological purposes, using the information theory, that enables selection of the most relevant variables. This technique also allows the examination of the asymmetrical relationships between variables. Applied to a set of physical and biological variables (plankton assemblages in four areas of the North Sea), the method shows that biological variables are more informative than physical variables although the controlling factors are mainly physical (sea surface temperature in winter and spring). Among biological variables, diversity measures and warm-water species assemblages are informative for the state of the North Sea pelagic ecosystems while among physical variables sea surface temperature in late winter and early spring are highly informative. Although often used in bioclimatology, the utilisation of the North Atlantic Oscillation (NAO) index does not seem to provide a lot of information. The method reveals that only the extreme states of this index has an influence on North Sea pelagic ecosystems. The substantial and persistent changes that were detected in the dynamic regime of the North Sea ecosystems and called regime shift are detected by the method and corresponds to the timing of other shifts described in the literature for some European Systems such as the Baltic and the Mediterranean Sea when both physical and biological variables are considered.  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