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   212篇
  免费   0篇
公路运输   13篇
综合类   9篇
水路运输   84篇
铁路运输   3篇
综合运输   103篇
  2020年   1篇
  2019年   6篇
  2018年   2篇
  2017年   1篇
  2016年   5篇
  2015年   1篇
  2014年   1篇
  2013年   67篇
  2012年   2篇
  2011年   7篇
  2010年   7篇
  2009年   8篇
  2008年   4篇
  2007年   8篇
  2006年   8篇
  2005年   2篇
  2004年   3篇
  2003年   2篇
  2002年   5篇
  2001年   2篇
  2000年   4篇
  1999年   4篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   3篇
  1994年   1篇
  1993年   1篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1985年   2篇
  1983年   4篇
  1982年   2篇
  1981年   5篇
  1980年   6篇
  1979年   4篇
  1978年   1篇
  1977年   3篇
  1976年   3篇
  1975年   2篇
  1974年   5篇
  1973年   2篇
排序方式: 共有212条查询结果,搜索用时 171 毫秒
181.
In September of 2000 the UK experienced a blockade of oil refineries in response to rising fuel prices. These protests resulted in severe fuel supply disruptions that intensified over the course of about one week. During the peak of the crisis, travel activity by car was curtailed. This paper analyzes survey data collected about two months after the crisis utilizing the recent memory of respondents as to how they would expect this sort of disruption to affect their participation in daily activities. Specifically, we focused on a variety of non-discretionary and discretionary activities and examined what factors are associated with respondents expecting disruption to those activities. Statistical models were developed to analyze how demographic factors, commute mode selection, vehicle characteristics, and various other factors can explain how individuals expect disruption to their activities. Results suggest that the majority of individuals do not expect major disruptions, although for more car-dependent individuals, disruption was expected to be substantial, especially for work-related trips. These results have implications for the potential success and benefits of an integrated transport policy.  相似文献   
182.
This paper first introduces the key players involved in the deployment of Intelligent Transportation Systems (ITS) technologies in the Los Angeles metropolitan area. The paper then reports the local deployment status of major Advanced Public Transportation Systems (APTS) projects, with a particular emphasis placed on the burgeoning Los Angeles Smart Shuttle Demonstration Project. In addition, the paper analyzes some technical, political, financial and other issues centering around the deployment of APTS technologies in the Los Angeles metropolitan area.  相似文献   
183.
We welcome the opportunity to respond to the issues raised in your critique to our paper. We take the comments as an indication of the interest the paper has sparked. Not often is shipping in the Caribbean a subject of academic concern and we are pleased to keep it in the spotlight. Let us deal with the issues in the order that they are raised.  相似文献   
184.
Georges Bank is one of the world's most highly productive marine areas, but the mechanisms of nutrient supply to support such high productivity remain poorly understood. Intrusions of nutrient-poor Labrador Slope Water (LSW) into the Gulf of Maine (NAO-dependent) potentially can reduce nutrient delivery to the bank, but this mechanism has not been quantitatively examined. In this paper, we present the first whole-year continuous model simulation results using a biological–physical model developed for the Gulf of Maine/Georges Bank region. This high-resolution three-dimensional coupled model consists of the Finite Volume Coastal Ocean Model (FVCOM) and a Nitrogen–Phytoplankton–Zooplankton–Detritus (NPZD) model, and was used to examine the influences of local and external processes on nitrogen and phytoplankton dynamics on Georges Bank. The model captured the general pattern of spatial-temporal distributions of nitrogen and phytoplankton and provided a diagnostic analysis of different processes that control nitrogen fluxes on Georges Bank. Specifically, numerical experiments were conducted to examine seasonal variation in nitrogen transport into the central bank (new nitrogen supply) versus nitrogen regenerated internally in this region. Compared with previous observation-based studies, the model provided a quantitative estimate of nitrogen flux by integrating the transport over a longer time period and a complete spatial domain. The results suggest that, during summer months, internal nitrogen regeneration is the major nitrogen source for primary production on the central bank, while nitrogen supply through physical transport (e.g. tidal pumping) contributes about 1/5 of the total nitrogen demand, with an estimated on-bank nitrogen transport at least 50% less than previous estimates. By comparing the model runs using different nitrogen concentrations in deep Slope Water, the potential influence of NAO-dependent intrusions of LSW was examined. The results suggest that the change of nitrogen concentration in the deep Slope Water may not have a significant impact on nitrogen and phytoplankton dynamics on the well-mixed central bank, largely due to limited nutrient exchange across the tidal mixing front and enhanced near-frontal nutrient uptake. However, relatively more significant impact was observed in the model simulations if both well-mixed and seasonally-stratified areas (inside 100 m isobath of the bank) were considered in flux calculations.  相似文献   
185.
This publication presents a three-part road classification system that utilises the vehicle's onboard signals of two-wheeled vehicles. First, a curve estimator was developed to identify and classify road curves. In addition, the curve estimator continuously classifies the road curviness. Second, the road slope was evaluated to determine the hilliness of a given road. Third, a modular road profile estimator has been developed to classify the road profile according to ISO 8608, which utilises the vehicle's transfer functions. The road profile estimator continuously classifies the driven road. The proposed methods for the classification of curviness, hilliness, and road roughness have been validated with measurements. The road classification system enables the collection of vehicle-independent field data of two-wheeled vehicles. The road properties are part of the customer usage profiles which are essential to define vehicle design targets.  相似文献   
186.
The effect of social interactions on decision-making is a topic of current interest in the travel behavior literature. These interactions have been investigated primarily from an intra-household perspective, but increasingly too in other types of social settings. In the case of interactions within a workplace, it has been suggested that the decision to telecommute may have some important social components. Previous research has concentrated on social isolation, and the effect on job satisfaction of qualitatively different (i.e., telecommunications-mediated) relationships with managers and colleagues. A topic that remains unexplored is the way social norms, in effect the influence of other people’s behavior, may influence the decision to adopt telecommuting. In this paper we set to investigate, within a qualitative framework, the role of social contact in the process of acquiring information on, and making decisions about, telecommuting. The results indicate that social contact does play a subtle but non-trivial role in the adoption and continuation process, and offer some insights about the importance of the social dimension, institutional set-up, and how they interact to influence the decision to telecommute.  相似文献   
187.
Positioned strategically between major east–west and north–south trading routes, the Caribbean basin has become a locus of new service configurations in container shipping. Over the last decade global shipping lines have been restructuring their service networks in the region in order to integrate local services with the newly rationalized intercontinental connections. By comparing service network structures in 1994 and 2002 at three levels of organization—local, regional and global—we are able to show that although Caribbean ports are well connected to the global system, and while the total number of services has declined between the two years, those mounted by members of global alliances have increased. Moreover, services of the global carriers at the local and regional levels are on the increase. As much as the alliances are reshaping Caribbean networks, the smaller carriers are still playing a role, but at a reduced spatial scale. Parallel with the modifications to network configurations are the changes in the port system. Essentially, traffic of the most important ports in the north and western part of the basin has grown at slower rates than the ports in the south and east. These traffic changes are only partly related to network changes. It is the growth of transshipments that is driving the most important developments in port traffic and bringing to the forefront the development of hub ports. The most important are: Colon, Panama (southwest), Freeport, Bahamas (north), Port of Spain, Trinidad and Tobago (southeast), Kingston, Jamaica and Rio Haina, Dominican Republic (middle), and Cartagena, Colombia and Puerto Cabello, Venezuela (south).  相似文献   
188.

This paper is addressed to the question of social costs and social benefits (primarily environmental) which might derive from a large‐scale substitution of so‐called mass‐transit for the present, largely private, system of automotive transportation. Energy consumption and emissions are compared for the two basic alternatives and several variants. Varying degrees of physiological tolerance to pollutants are taken into account, in an attempt to develop comparable weight‐factors for different types of emissions. It is suggested that if automobiles succeed in meeting the 1975/76 emission standards set by the Clean Air Act of 1970, rail rapid transit will probably offer no advantage (in environmental terms) unless electric power is available from virtually non‐polluting sources (e.g., natural gas or nuclear plants). Economic implications of large‐scale substitution are examined, and it is noted that such substitution would involve major restructuring of our society as a whole. However, more intensive use of mass transit in central cities, possibly in conjunction with various measures to discourage the use of private automobiles in very congested areas is feasible and likely.  相似文献   
189.
Robert Watson 《运输评论》2013,33(2):181-193

The restructuring of the UK railway industry in preparation for privatization led to major changes being made to train planning processes. Subsequent train planning problems, some of which became very public, suggest that something went seriously wrong during the development or implementation of these revised processes. This paper investigates what went wrong and why, finding that several factors were involved, including the objectives the new processes were expected to meet and the software that was being developed to support the new processes. There are clear lessons to be learnt from the UK experience to inform debate on future railway restructuring initiatives.  相似文献   
190.

The use of third-party logistics services by large US manufacturers continues to grow. Increasingly, those services are used to support international sourcing and sales activities. Use of these services is often triggered by specific events such as a corporate restructuring, a top management change or a benchmarking effort. Nearly two-thirds of users report they experienced significant impediments in implementing third-party agreements. After starting conservatively, the typical user buys a wide variety of logistics services. Users generally report that buying logistics services has had a positive impact on their organizations, particularly with respect to logistics costs and customer service. However, many also report negative impact on employee morale linked to downsizing the logistics workforce. More than two-thirds of users report cancelling at least one-third-party logistics contract. Nevertheless, if given complete responsibility to make the decision, >70% of users would increase their companies' use of such services.  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