全文获取类型
收费全文 | 2680篇 |
免费 | 146篇 |
专业分类
公路运输 | 532篇 |
综合类 | 971篇 |
水路运输 | 416篇 |
铁路运输 | 371篇 |
综合运输 | 536篇 |
出版年
2024年 | 8篇 |
2023年 | 12篇 |
2022年 | 31篇 |
2021年 | 59篇 |
2020年 | 86篇 |
2019年 | 53篇 |
2018年 | 85篇 |
2017年 | 85篇 |
2016年 | 107篇 |
2015年 | 120篇 |
2014年 | 202篇 |
2013年 | 272篇 |
2012年 | 181篇 |
2011年 | 203篇 |
2010年 | 203篇 |
2009年 | 162篇 |
2008年 | 178篇 |
2007年 | 182篇 |
2006年 | 184篇 |
2005年 | 101篇 |
2004年 | 72篇 |
2003年 | 62篇 |
2002年 | 37篇 |
2001年 | 43篇 |
2000年 | 23篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 6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2826条查询结果,搜索用时 0 毫秒
81.
为解决内河一类船长实操考试效能评估问题,提出了一种基于模糊认知图的评价模型(FCMES).在建立影响因素层的不同评价等级基础上,通过问卷调查辨识出了25个影响因素;据专家意见将收集到的定性数据转化为三角模糊数,得到不同的模糊矩阵;利用模糊推理规则的方法聚合各模糊矩阵,再解模糊化,获取邻接矩阵.采取输入端数、输出端数及中心度3个指数的方法,分析FCMES中各因素的重要程度,选出核心变量.利用Matlab实现对FCMES认知图的推理仿真,检验核心变量的准确性.结果表明,绩效评估、评估员素质、模拟器效能、考试流程设计合理性,这4个影响因素对内河一类船长实操考试的效能有重要影响. 相似文献
82.
Natalia Selini Hadjidimitriou Marco Mamei Mauro Dell'Amico Ioannis Kaparias 《智能交通系统杂志
》2017,21(5):375-389
》2017,21(5):375-389
With the increasing use of Intelligent Transport Systems, large amounts of data are created. Innovative information services are introduced and new forms of data are available, which could be used to understand the behavior of travelers and the dynamics of people flows. This work analyzes the requests for real-time arrivals of bus routes at stops in London made by travelers using Transport for London's LiveBus Arrivals system. The available dataset consists of about one million requests for real-time arrivals for each of the 28 days under observation. These data are analyzed for different purposes. LiveBus Arrivals users are classified based on a set of features and using K-Means, Expectation Maximization, Logistic regression, One-level decision tree, Decision Tree, Random Forest, and Support Vector Machine (SVM) by Sequential Minimal Optimization (SMO). The results of the study indicate that the LiveBus Arrivals requests can be classified into six main behaviors. It was found that the classification-based approaches produce better results than the clustering-based ones. The most accurate results were obtained with the SVM-SMO methodology (Precision of 97%). Furthermore, the behavior within the six classes of users is analyzed to better understand how users take advantage of the LiveBus Arrivals service. It was found that the 37% of users can be classified as interchange users. This classification could form the basis of a more personalized LiveBus Arrivals application in future, which could support management and planning by revealing how public transport and related services are actually used or update information on commuters. 相似文献
83.
为降低回收处理危险废物的环境危害,提出了基于环境风险控制的危险废物选址-路径问题,全面地评估了危险废物回收管理的环境风险.根据环境承载力的理论,设计了环境风险的度量方法.考虑废物残余的危险性、危险废物类型和加工技术种类的多样性、危险废物和加工技术的相容性,建立了成本最小化和环境风险最小化的0-1混合整数线性规划模型.针对双目标选址-路径模型的复杂性特点,设计了多阶段聚类遗传算法.以重庆危险废物物流管理为例,验证了模型和算法的有效性.结果表明:模型和算法能够为实际管理提供合理的选址-路径优化方案,且在两个不同对比条件下,相较于已有的模型,基于环境风险控制的优化方案能够分别降低33.85%和18.16%的总成本. 相似文献
84.
85.
Firman Permana Wandani Maimunah Siti Masashi Yamamoto Yuichiro Yoshida 《国际交通安全学会研究报告》2018,42(2):76-85
The purpose of this paper is to verify the justification provided for a centralized national road policyin Indonesia, namely, that trips on national roads are typically inter-urban, by measuring the spatialdimensions of automobile and motorcycle trips on national roads in Indonesia. The study finds thatmotorcycle trips are characteristically local; by contrast, automobile trips extend beyond city boundaries,although to a limited extent. The results suggest the decentralization of transportation policies for thedevelopment and maintenance of national roads by granting autonomy to local governments when nofiscal externality exists. The results also indicate that road capacity, gasoline prices, income, populationand worker density, city size, and the number of public buses are strong predictors of vehicle kilometerstraveled. 相似文献
86.
87.
Rural areas generally have lower and more dispersed demands for travel which cannot sustain conventional public transport services and consequently have a greater number of flexible and demand responsive transport services operating. These services usually operate on a stand-alone basis, are often subsidized and are typically only accessible by certain passenger types or for specific trip purposes. This generally results in uncoordinated and inefficient transport provision overall. The Flexible integrated transport services (FITS) system featured in this paper has been designed to address this problem. FITS can be used as a planning tool to assess potential benefits from relaxing operating constraints (e.g., a service's operating boundaries), which can potentially suggest service redesign. It also includes the capacity to assign subsidy payments on a trip by trip basis to increase cost efficiency whilst meeting a greater proportion of transport needs. The case study in the paper focusses on transport to health in the Aberdeenshire and Morayshire areas of Scotland in the UK. Despite flexible transport operators receiving public funds to meet passenger needs, this is currently being supplemented by public bodies paying large amounts in taxi fares in instances where there is a statutory obligation to provide travel but where no other suitable transport service exists. The results demonstrate the potential substantial savings which could be realized by allowing transport operators to redesign their services by relaxing constraints and by the reassignment of subsidies: resulting in more passenger demands being met and a reduction in public spending on taxi fares. 相似文献
88.
为控制危险品运输风险大小并提高风险分布合理性,兼顾运输商的利益诉求,对多种类型危险品在同一路网内运输时的多路径组合优化问题进行研究。首先根据运输路径物理特征,结合路段风险值给出路径间的物理相异度计算方法,并根据各路段在路网内的地理位置,给出路径间的空间相异度计算方法;然后设置总风险阈值和最小相异度约束,建立同时考虑累积运输风险、运输费用和运输时间的多目标优化模型,改进第2代非支配排序遗传算法(Non-dominated Sorting Genetic Algorithm-Ⅱ,NSGA-Ⅱ)对模型求解,利用动态拥挤距离来提高群体中个体分布的均匀性;最后通过随机网格网络算例对多种类型危险品在不同起讫点间单次、多次运输场景下的路径选择进行仿真优化,并利用实际路网数据对优化方法的可行性进行验证。结果表明:设置危险品运输路径之间的相异度约束,可减少共用路段/节点数量,避免运输风险在局部区域内过度集中;适当增加累积运输风险,有利于提高路径之间的物理相异度和空间相异度,使运输风险的分布更为分散,同时扩大了运输商的路径优化空间。研究结果可为政府部门对危险品运输风险控制及风险分布管理提供新的方法,为运输商的路径选择提供决策支持。 相似文献
89.
居民出行调查是城市交通规划、建设和管理的基本依据.本文根据宜兴市2002年居民出行调查的有关数据,对人均出行次数、平均出行时耗、出行方式构成、出行目的和出行时间分布等进行了分析,并在此基础上,结合宜兴市交通现状及城市总体规划,从优先发展公共交通、重视自行车交通、控制摩托丰发展、加强交通管制、强化市场机制、加强企业管理和政府扶持相结合以及颁布公交行业服务标准等方面,提出了宜兴市客运交通发展的几点对策. 相似文献
90.
通过对广东省公路客运企业和政府主管部门的问卷调查,采用因子分析方法,从影响客运市场退出的相关主体及相关行为中筛选出关键变量.运用非参数检验过程,就各关键变量对退出的影响程度进行比较,最终得出驾驶员和承包经营人的相关行为对公路客运市场退出最具影响的结论,为政府部门进行行业管理和政策制定提供了实证依据. 相似文献