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   474篇
  免费   44篇
公路运输   82篇
综合类   133篇
水路运输   177篇
铁路运输   93篇
综合运输   33篇
  2024年   4篇
  2023年   3篇
  2022年   8篇
  2021年   14篇
  2020年   26篇
  2019年   21篇
  2018年   11篇
  2017年   17篇
  2016年   22篇
  2015年   28篇
  2014年   42篇
  2013年   42篇
  2012年   44篇
  2011年   37篇
  2010年   27篇
  2009年   35篇
  2008年   19篇
  2007年   29篇
  2006年   27篇
  2005年   19篇
  2004年   6篇
  2003年   7篇
  2002年   7篇
  2001年   5篇
  2000年   4篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
  1994年   2篇
  1993年   2篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
排序方式: 共有518条查询结果,搜索用时 125 毫秒
11.
为构建客货船舶协同动态运行控制技术体系,以经典航道通过能力模型为基础,构建基于游览船运营特征(发船高峰性和航线集中度)的航道通过能力模型.根据黄浦江游览核心区船舶自动识别系统(AIS)数据,对所提出的航道通过能力模型进行实证分析.研究结果表明,本文航道通过能力模型能够较为准确地评价研究区域的实际航道通过能力.游览船发船高峰时期与现有航线规划条件下,黄浦江游览核心区航道通过能力(76艘/h)趋近饱和状态;当过境船到达超过69艘/h时,建议海事相关部门采取“错峰”航行等相关政策.  相似文献   
12.
Highways and freeways are the main infrastructure channel used to transport cargo in Brazil. This cargo often includes dangerous chemical products which can, in the event of an accident, negatively impact the environment. The development and implementation of tools for the rapid diagnosis of environmental vulnerability in the transportation of dangerous goods has been studied. However, for highways and freeways there is a lack of studies based on environmental attributes, and not just based on statistical data which demands a specific period for collection and analysis and only after that the implementation of preventive measures. Thus, evaluation grounded on multiple criteria embedded in Geographic Information System (GIS) has significant potential for the practical implementation of risk management of road transportation of dangerous goods. This study has determined the environmental vulnerability of route BR 050, specifically the segment between the cities of Uberlândia and Uberaba in the state of Minas Gerais, where multi criteria analysis has been efficient in determining the most vulnerable areas. The main attributes analyzed were the drainage density, soil type and geology, determining that in case of an accident with dangerous substances the regional environment would be immediately affected, and so endorsing the use of this tool in many segments involved in environmental management of highway enterprises.  相似文献   
13.
Building safe and effective roundabouts requires optimizing traffic (operational) efficiency (TE) and traffic safety (TS) while taking into account geometric factors, traffic characteristics and local constraints. Most existing simulation-based optimization models do not simultaneously optimize all these factors. To capture the relationship among geometry, efficiency and safety, we put forward a model formulation in this paper. We present a new multi-criteria and simultaneous multi-objective optimization (MOO) model approach to optimize geometry, TE and TS of urban unsignalized single-lane roundabouts. To the best of our knowledge, this is the first model that uses the multi-criteria decision-making method known as analytic hierarchy process to evaluate and rank traffic parameters and geometric elements of urban single-lane roundabouts. The model was built based on comprehensive review of the research literature and existing roundabout simulation software, a field survey of 61 civil and traffic expert engineers in Croatia, and field studies of roundabouts in the Croatian capital city of Zagreb. We started from the basis of Kimber’s capacity model, HCM2010 serviceability model, and Maycock and Hall's accident prediction model, which we extended by adding sensitivity analysis and powerful MOO procedures of the bounded objective function method and interactive optimization. Preliminary validation of the model was achieved by identifying the optimal and most robust of three geometric alternatives (V.1-V.3) for an unsignalized single-lane roundabout in Zagreb, Croatia. The geometric parameters in variant V.1 had significantly higher values than in the existing design V.0, while approaches 1 and 3 in variant V.2 were enlarged as much as possible within allowed spatial limits and Croatian guidelines, reflecting their higher traffic demand. Sensitivity analysis indicated that variant V.2 showed the overall highest TE and TS across the entire range of traffic flow demand and pedestrian crossing flow demand at approaches. At the same time, the number of predicted traffic accidents was similar for all three variants, although it was lowest overall for V.2. The similarity in predicted accident frequency for the three variants suggests that V.2 provides the greatest safety within the predefined constraints and parameter ranges explored in our study. These preliminary results suggest that the proposed model can optimize geometry, TE and TS of urban single-lane roundabouts.  相似文献   
14.
通过调研和总结上海已建15座盾构隧道的设计资料,对现有隧道存在的病害进行了归类分析,提出了隧道病害的预防与治理措施;对明挖段的围护设计选型、结构工程规模和盾构隧道几何设计参数进行了统计分析,提出了明挖接线段围护结构选型及插入比的建议,明确了明挖结构的计算模型和计算参数;对已建盾构隧道的埋深、最小曲线半径、最小线间距、最大坡度等几何参数进行了详细分析,总结出了工作井平面尺寸的确定方法和盾构进出洞的关键技术。  相似文献   
15.
以大连港东部地区搬迁改造项目游艇码头工程的地基处理为例,通过对工程试验区的研究,提出了合理的设计标准和施工工艺方法。通过对碎石桩质量检测的研究,提出了通过沉箱压载试验和重型动力触探相结合的方式对碎石桩质量进行检测,分析了该项目中碎石桩成桩效果,总结了水上振冲法在低强度饱和黏性土中的工程经验及质量检测标准。  相似文献   
16.
铁路提速对我国国防交通动员带来了深刻影响:对铁路动员信息化建设、优化国防交通运输格局、提高铁路快速动员能力和加快专业技术队伍建设等提出了新的要求,应充分发挥动员潜力,全面加强铁路动员指挥网络、铁路军运衔接工程、运输人才队伍和运输保障队伍等方面的建设,完善铁路运输军代体系等运行机制,提升铁路运输动员综合效能。  相似文献   
17.
地铁车站空气品质的评价与探讨   总被引:1,自引:0,他引:1  
介绍了室内空气品质的定义,归纳了地铁车站空气品质的评价方法和标准.经研究对比指出,在对地铁车站空气进行评价时使用卫生标准比舒适性标准更为合适.影响地铁车站空气品质的主要因素有空调系统的材质问题、室内空气的二次污染、由于活塞风带来的隧道空气等.最后,提出了一些相关的改善措施,如清除和控制室内污染源、发挥通风有效性、装屏蔽门、制定针对地铁站的空气质量标准等.  相似文献   
18.
A vehicle assignment problem (VAP) in a road, long‐haul, passenger transportation company with heterogeneous fleet of buses is considered in the paper. The mathematical model of the VAP is formulated in terms of multiobjective, combinatorial optimization. It has a strategic, long‐term character and takes into account four criteria that represent interests of both passengers and the company's management. The decision consists in the definition of weekly operating frequency (number of rides per week) of buses on international routes between Polish and Western European cities. The VAP is solved in a step‐wise procedure. In the first step a sample of efficient (Pareto‐optimal) solutions is generated using an original metaheuristic method called Pareto Memetic Algorithm (PMA). In the second step this sample is reviewed and evaluated by the Decision Maker (DM). In this phase an interactive, multiple criteria analysis method with graphical facilities, called Light Beam Search (LBS), is applied. The method helps the DM to define his/her preferences, direct the search process and select the most satisfactory solution.  相似文献   
19.
本文将安全水平法应用于SOLAS第III章救生艇结构强度衡准的制定。主要采用综合安全评估对救生艇结构强度相关的功能性要求进行衡准的初步制定,从而得出需要的安全水平。基于强度衡准理论分析、实艇试验和事故数据分析相结合的方式评估了现有救生艇结构强度的安全水平,对衡准的合理性提出修改的建议。研究结果为安全水平法在船舶技术标准制定和安全水平评估方面的应用提供了实际案例和使用建议。  相似文献   
20.
廖军 《交通标准化》2007,(5):181-184
为了优化资源,降低物流成本,提高物流运输可靠度和速度,需要建立恰当的西南公路出海(辅助)通道的物流运作模式,以充分发挥出西南公路出海(辅助)通道基础建设的效益.  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