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431.
Electric vehicles (EVs) are considered as a feasible alternative to traditional vehicles. Few studies have addressed the impacts of policies supporting EVs in urban freight transport. To cast light on this topic, we established a framework combining an optimization model with economic analysis to determine the optimal behavior of an individual delivery service provider company and social impacts (e.g., externalities and welfare) in response to policies designed to support EVs, such as purchase subsidy, limited access (zone fee) to congestion/low-emission zones with exemptions for EVs, and vehicle taxes with exemptions for EVs. Numerical experiments showed that the zone fee can increase the company’s total logistics costs but improve the social welfare. It greatly reduced the external cost inside the congestion/low-emission zone with a high population, dense pollution, and heavy traffic. The vehicle taxes and subsidy were found to have the same influence on the company and society, although they have different effects with low tax/subsidy rates because their different effects on vehicle routing plans. Finally, we performed a sensitivity analysis. Local factors at the company and city levels (e.g., types of vehicle and transport network) are also important to designing efficient policies for urban logistics that support EVs. 相似文献
432.
433.
航运市场运费套期保值方法探讨 总被引:2,自引:0,他引:2
分析研究了2种运费套期保值方法远期运价协议和运价指数期货合约,通过典型案例论证了租船人和船东都能利用这2种方法,锁定运费收入或支出,从而规避运价风险的目的;同时对这2种方法进行了分析比较,指出运价指数期货合约具有灵活性且安全的特点,但二者费用有差异,运价指数期货合约需要一定的保证金,实际费用等于经纪人的佣金(通常为0.3%)加上现金保证金的利息。 相似文献
434.
回归分析方法在VTS预测研究中的应用 总被引:2,自引:1,他引:1
该文将数理统计中的回归分析方法应用到VTS预测研究中,其预测结果有较高的精度,是基础理论应用于工程实际的有益实践,为VTS规划研究提供了一种实用的预测方法。 相似文献
435.
120km/h交流传动货运电力机车研制构想 总被引:1,自引:0,他引:1
铁路货运提速急需120km/h速度等级的牵引机型,6轴(C0-C0)大功率交流传动电力机车是最佳的机型选择。文章对拟研制的车型进行了技术构思,提出了机车的主要技术建议参数,并对研制的关键技术难点和运用范围进行了说明。 相似文献
436.
The paper presents and analyses appraisal methods used for the assessment of potential investments in Nodal Centers for Goods
(also called Freight Villages), which constitute an essential element of the Trans-European Network for Intermodal Transport.
A methodological procedure is applied to identify the underlying factors that influence the choice of an appraisal method,
without assessing or comparing the appraisal methods themselves. Following this procedure, issues addressed by the methods
are grouped into three broad dimensions and with the use of non-parametric statistical tests, existing relationships are identified
between nodal centres' characteristics, the appraisal methods, as well as the actors involved in the decision process. On
applying the above procedure to European Nodal Centres for goods, it is found that the choice of appraisal method and the
decision criteria for the investment are linked primarily to the nodal centre's size, catchment area, and the support or absence
of political approval for the investment. The results of the analysis can be particularly useful at the policy making level,
serving as non-formal "qualitative guidelines" to identify the appraisal method to be applied, as well as the options and
impacts to be considered.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
437.
铁路货运量组合预测方法 总被引:1,自引:0,他引:1
为了对铁路货运量进行科学预测,在指数平滑、模糊移动、线性回归、灰色预测4种单一模型的基础上建立组合预测模型。结果表明:组合预测模型能有效综合各模型的有用信息,并能提高其预测精度,预测结果可靠。与单一模型相比,该法具有较好的实用价值。 相似文献
438.
通过大秦线牵引重载列车的货运电力机车钩缓系统近年来应用情况调研分析和计算比较,参考美国等国家重载货运机车用钩缓应用情况,探讨我国重载货运电力机车钩缓系统的基本特性参数及其选型范围,指出我国重载货运电力机车钩缓系统未来发展的趋势和方向。 相似文献
439.
440.