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   232篇
  免费   3篇
公路运输   27篇
综合类   100篇
水路运输   51篇
铁路运输   15篇
综合运输   42篇
  2022年   6篇
  2021年   9篇
  2020年   4篇
  2019年   6篇
  2018年   9篇
  2017年   6篇
  2016年   7篇
  2015年   5篇
  2014年   13篇
  2013年   19篇
  2012年   11篇
  2011年   13篇
  2010年   13篇
  2009年   18篇
  2008年   10篇
  2007年   23篇
  2006年   13篇
  2005年   10篇
  2004年   13篇
  2003年   4篇
  2002年   8篇
  2001年   6篇
  2000年   2篇
  1999年   2篇
  1998年   1篇
  1993年   1篇
  1991年   1篇
  1989年   1篇
  1986年   1篇
排序方式: 共有235条查询结果,搜索用时 15 毫秒
191.
基于对策论的原理,分析了高速公路和铁路运输的收费定价问题.以道路经营者为研究主体,建立了对策模型,研究在自由竞争的情况下高速公路和铁路一方的定价行为对另一方产生的影响.在双方都以利润最大化为目的前提下,得出影响收费定价的各个因素,以及双方在定价博弈中的相互制约程度,使收费定价达到均衡状态.给出了铁路公司与公路公司相互之间的反应函数,并通过此反应函数得到了最优均衡状态下的收费定价,在一定程度上为铁路和高速公路经营者提供了定价依据.  相似文献   
192.
Appropriate port regulation and competitive forces tend to be related to higher levels of operational and economic performance of ports. From a policy-making perspective, pursuing efficiency and securing competition in ports to reach a level playing field is a two-step process requiring (1) ex-ante regulations to set the rules that maximize the competition for the market, especially when the policy objective is to attract private operations to ports on competitive concession processes and (2) ex-post competition policy to monitor and preserve competition in the market. This paper studies port regulation in Latin America and the Caribbean (LAC) from a competition perspective, analyzing both ex-ante and ex-post policies implemented in the region. The analysis reveals that the competitive environment in LAC is low, giving room for possible anticompetitive practices in the LAC port sector. Since the end of the 1990s, approximately 80% of container terminals in the region were granted to only five companies. Chile and Mexico have been found to be the best practices in the region, with better conditions assuring robust competition in the market. The main policy implication from this analysis is the need for a stronger involvement of antitrust agencies throughout the port concession processes.  相似文献   
193.
技能大赛作为职业教育的组成部分,在职业教育发展中始终起着积极的促进作用,在国家将职业教育作为类型教育大力发展的战略机遇期下,其重要性越发凸显.全国性的技能大赛获奖对参赛师生和所在院校都具有极高的附加值,因此,各个省区市相关院校都在全力以赴争取冲进国赛.本文简单介绍了职业院校技能大赛的现状,充分肯定了其在推动实践教学方面...  相似文献   
194.
林克  王洪梅 《机电设备》2010,27(2):27-30,18
自动发电控制(AGC)作为能量管理系统(EMS)中最重要的控制功能之一,能有效的提高电网互联系统频率质量,提高经济效益和管理水平.但随着我国电力系统市场化体制改革的不断深入和完善,互联系统原先以TBC模式为主的频率控制方式就成了电力市场环境下互联系统区域间交易的壁垒,同时大用户与发电机组的直供电需求也越来越迫切.为了促进大用户直供电运行方式的深入实施,本文从技术上提出一种支持大用户与发电机组间直供电的互联系统AGC改进模式.  相似文献   
195.
成渝两地高速公路客运经营策略研究   总被引:2,自引:0,他引:2  
成都与重庆作为我国西南地区的两个特大城市,经济联系非常密切,长期以来,一直由公路、铁路、民航三种运输方式共同承担着两地的旅客运输任务,竞争非常激烈.遂渝准高速铁路通车后,再度掀起了成渝两地间客运的激烈竞争,铁路运输"安全、舒适、运价低"的优势给高速公路与民航客运带来了巨大压力.回顾了成渝两地间三种运输方式的客运竞争历史,分析了未来两地间旅客运输的竞争局势,采用SWOT分析法研究了高速公路客运在特定竞争环境下的经营战略问题,提出应及时实施战略转移,并相应提出了六项具体的防御性竞争策略.  相似文献   
196.
This paper analyzes the effects of integration between two neighbor ports with a third port sharing the same overlapping hinterland. The merger (integrated port) can select either the price discrimination or uniform pricing strategy after integration. Our study reveals that port integration is always beneficial to the merger and the third port, but results in the reduction of consumer surplus and social welfare, regardless of the type of pricing strategy implemented. Further analysis shows that when the inland transportation cost to the ports is relatively low or sufficiently high, a better option is for the merger to adopt the price discrimination strategy. When port pollution is considered and has a relatively large impact, the integration of the two ports improves green social welfare for the region. This finding provides strong support for the ongoing port integration in China. In terms of pricing strategy, the uniform pricing strategy generates higher green social welfare when both inland transportation cost and pollution are relatively low, or both are significantly high. Otherwise, the price discrimination strategy generates the best result for the region.  相似文献   
197.
The paper first briefly reviews the extent to which profit maximising transport firms with identical cost functions and producing identical transport services pass-on output taxes to transport users under perfect competition, under different forms of imperfect competition and when they act as monopolists. Then the analysis is extended to derive the pass-on rates and activity reductions caused by an output tax when firms care both about profit and consumer surplus, produce symmetrically differentiated services and compete simultaneously in quantities and fare and when they collude. The pass-on rates and activity reductions are highest under collusion and lowest under Cournot competition when they produce complementary services. When they produce substitute services, the result is ambiguous and the competitive situation that yields highest pass-on depends on the firms’ objective functions and how fiercely they compete. Two important counterintuitive results are that the more intensely the firms compete and the more weight they put on consumer surplus, the higher the pass-on rates are.  相似文献   
198.
This paper tests whether, and to what extent, airlines exploit market captivity by using price discrimination strategies. The Italian passenger market is particularly fit for this purpose, given the high differentials in the degree of the inter-modal competition amongst domestic connections. Results show that, ceteris paribus, airlines adopt a different pricing behaviour depending on the degree of inter-modal market captivity. First, in highly concentrated markets with respect to air competitors, airlines price higher when the inter-modal competition is limited. This proves that inter-modal market captivity strengthens the effect of market power. Second, the inter-temporal price discrimination leads to a J-shaped distribution of fares over time, which is more pronounced when the inter-modal competition is effective. This suggests that airlines need to adopt a pricing technique that allows for a greater market segmentation in order to compete successfully with high-speed rail transport and to extract a larger part of passengers’ surplus. These results are relevant in terms of transport-investment implications and competition policy. The indirect benefits that investments in rail infrastructure would yield through downward pressures on competing airline fares should be embedded in any cost-benefit analysis of high-speed networks investments and in any policy evaluation of measures that aim to reduce the territorial gaps in infrastructure endowment and accessibility.  相似文献   
199.
Technological paradigm shifts often come with a newly emerging industry that seeks a viable infrastructure deployment plan to compete against established competitors. Such phenomenon has been repeatedly seen in the field of transportation systems, such as those related to the booming bioenergy production, among others. We develop a game-theoretic modeling framework using a continuum approximation scheme to address the impacts of competition on the optimal infrastructure deployment. Furthermore, we extend the model to incorporate uncertainties in supply/demand and the risk of facility disruptions. Analytical properties of the optimal infrastructure system are obtained, based on which fast numerical solution algorithms are developed. Several hypothetical problem instances are used to illustrate the effectiveness of the proposed algorithms and to quantify the impacts of various system parameters. A large-scale biofuel industry case study for the U.S. Midwest is conducted to obtain additional managerial insights.  相似文献   
200.
This paper analyses whether the current provision of air services in Europe is impacted by high-speed rail (HSR). An ex-post analysis is carried out considering 161 routes EU-wide using transnational data. We use censored regressions with special attention paid to the presence of outliers in the sample and to the potential problem of non-normality of error terms. It is found that shorter HSR travel times involve less air services, with similar impact on both airline seats and flights. This impact quickly drops between 2.0- and 2.5-h HSR travel time. The impact of HSR frequencies is much more limited. Hubbing strategies led by the airlines have the opposite effect from HSR, as hubs involve more air services. Airline/HSR integration at the airport and cities being served by both central and peripheral stations have no significant impact. Metropolitan and national spatial patterns may help to better understand intermodal effects.  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