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491.
A number of studies have shown that in addition to travel time and cost as the common influences on mode, route and departure time choices, travel time variability plays an increasingly important role, especially in the presence of traffic congestion on roads and crowding on public transport. The dominant focus of modelling and implementation of optimal pricing that incorporates trip time variability has been in the context of road pricing for cars. The main objective of this paper is to introduce a non-trivial extension to the existing literature on optimal pricing in a multimodal setting, building in the role of travel time variability as a source of disutility for car and bus users. We estimate the effect of variability in travel time and bus headway on optimal prices (i.e., tolls for cars and fares for buses) and optimal bus capacity (i.e., frequencies and size) accounting for crowding on buses, under a social welfare maximisation framework. Travel time variability is included by adopting the well-known mean–variance model, using an empirical relationship between the mean and standard deviation of travel times. We illustrate our model with an application to a highly congested corridor with cars, buses and walking as travel alternatives in Sydney, Australia. There are three main findings that have immediate policy implications: (i) including travel time variability results in higher optimal car tolls and substantial increases in toll revenue, while optimal bus fares remain almost unchanged; (ii) when bus headways are variable, the inclusion of travel time variability as a source of disutility for users yields higher optimal bus frequencies; and (iii) including both travel time variability and crowding discomfort leads to higher optimal bus sizes.  相似文献   
492.
There is growing interest in establishing additional evidence, under the umbrella of the wider economy impacts of transport infrastructure projects, to support transport projects in general and public transport projects in particular that struggle to obtain benefit–cost ratios sufficient to gain the support of financial agencies. This paper focuses on one element of wider economy impacts, often referred to as effective economic (employment) density or employment agglomeration impacts, and another, less usually identified, social accessibility impact (SAI) which we refer to as effective social density, which in broad terms provide, correspondingly, evidence of the potential gains in work-related output (often referred to as productivity gains) and potential gains in non-work-related outputs. Both are associated with gains in individual and household benefit attributable to improved accessibility to services linked with populations and particular locations. The SAIs may capture some of the induced benefits in those jurisdictions where these are included routinely in benefit–cost analysis, and the methodology here is most appropriate to those settings where an existing calibrated demand curve may not be available. Using the proposed high speed rail (HSR) project between Sydney and Melbourne as the empirical setting, we identify economic agglomeration and social accessibility benefits for work and non-work related activity respectively. We find the former to be relatively small compared to the significant gains associated with non-work related travel activity, suggesting the greatest benefits associated with HSR, especially for those residents outside of the major metropolitan areas, will be non-work related travel activity.  相似文献   
493.
Hardware-in-the-loop (HIL) simulation is a promising technique to study the pantograph–catenary interaction problems by realising the interaction of a physical pantograph with a mathematical model of the overhead equipment (catenary). However, the computing power presently available on real-time CPUs only allows to run simplified models of the overhead equipment. Therefore, it is important to define catenary models that are suitable for real-time simulation and at the same time capable of accurately representing the dynamic behaviour of the catenary. In this paper, the use of a catenary model based on modal superposition is considered, and the effect of changing the number of modelled spans and the number of modal components allocated to the contact and messenger wires is investigated in view of finding the best model compatible with real-time simulation. Comparisons between HIL simulation results and line measurements are presented, to quantify the accuracy of the hybrid simulation method developed.  相似文献   
494.
The first field experiment with intelligent speed adaptation (ISA) in Malaysia was held in December 2010 in the State of Penang. Eleven private cars were instrumented with an advisory system. The system used in the present study included a vocal warning message and a visual text message that is activated when the driver attempts to exceed the speed limit. When the driver decreases the speed, the warning stops; otherwise it is continuously repeated. The test drivers drove the vehicles for three months with the installed system, and the speed was continuously logged in all vehicles. The warning was however only activated in the second month of the three month period. The present study aimed to evaluate the effects of an advisory ISA on driving speed, traffic safety, and drivers' attitude, behavior, and acceptance of the system. To examine these effects, both the survey and the logged speed data were analyzed and explored. The results show a significant reduction in the mean, maximum and 85th percentile speed due to the use of the system. However, there was no long-lasting effect on the speed when the system was deactivated. In the post-trial survey, drivers declared that the system helped them well in following the speed limits and that it assisted them in driving more comfortably. Furthermore, the warning method was more accepted compared to a supportive system, such as active accelerator pedal (AAP). After the trial, most drivers were willing to keep an ISA system.  相似文献   
495.
This paper tests two fundamental hypotheses concerning international maritime statistics. The first one deals with the question of stationary of the maritime market statistics. The second hypothesis tested is the assumption that the international maritime statistical time series are not distributed according to a normal of Guassian probability law, but rather belong to the same family of distributions with distinctly different critical parameters. Through well documented statistical methods, the paper concludes that the international freight rates observed on a day to day basis are generated by a random walk process. The paper finds that the shipping industry's conventioal wisdom is essentially correct. ‘Last done’ is as good a forecast of tomorrow's freight rate as any other generated by more sophisticated forecasting methods. Furthermore, freight rates and secondhand tonnage prices fluctuate closely together. The freight rates are generated by stochastic processes fully described by the Paretian family of distributions. The critical parameters of these distribution, the characteristic exponents, are such that the risk conscious ship operator can indeed reduce his exposure to risk by securing a correct set of freight rate contracts.  相似文献   
496.
Travel time variability (i.e., random variations in travel time) leads to a travel time distribution for a repeated trip from a fixed origin to destination (e.g., from home to work). To represent travel time variability, a series of possible travel times per alternative (departure time, route or mode) are often used in stated choice experiments. In the traditional models, the probabilities associated with different travel scenarios (e.g., arriving early, on time and late) shown in the experiments are directly used as weights. However, evidence from psychology suggests that the shown probabilities may be transformed (underweighted or overweighted) by respondents. To account for this transformation of probabilities, this study incorporates perceptual conditioning through a non-linear probability weighting function into a utility maximisation framework, within which the empirical estimate of the value of expected travel time savings is estimated. The key advantage of this framework is that the estimated willingness to pay value can be directly linked to the source of utility (i.e., the probability distribution of travel time), while taking into account the perceptual transformation of probabilities.  相似文献   
497.
Site-based projects were initiated in Chawka Bay-Paje, Zanzibar, and Nyali-Bamburi-Shanzu, Kenya, to demonstrate the benefits of an integrated coastal management (ICM) approach for addressing coastal issues such as tourism development and enhancement of resource-dependent village economies in eastern Africa. A two-year, multidonor project used three primary strategies to make rapid, but sustainable, progress toward ICM. These included using interagency government teams for ICM planning, adopting an internationally recognized framework for ICM as a project ''road map,'' and explicitly incorporating capacity-building strategies into all aspects of the project. Within two years, integrated ICM action strategies, prepared through participatory processes, were being implemented at both sites, and both teams were working to expand the scale and scope of ICM in their nation. More importantly, the project helped create committed, capable, interagency groups that continue to work together to address urgent ICM issues.  相似文献   
498.
As tourists are sensitive to weather conditions and changes to the environments they visit, it is likely that climate change will affect coastal recreation in the future. To understand these impacts, it is first important to quantify how visitor numbers are associated with beach characteristics and weather patterns. Using the East Anglian coastline, UK, as a case study, information on the spatial distribution of visitors recorded from aircraft flights is combined with beach characteristic data in a Geographical Information System. In addition, surveys are undertaken at two beaches to assess temporal variations in visitation. The study finds a diverse range of characteristics are associated with visitor numbers. These findings are evaluated alongside the anticipated effects of climate change and management policies. Although it is predicted that warmer weather will increase visitor numbers overall, sea-level rise may reduce numbers at wide sandy beaches, which are currently most preferred by tourists.  相似文献   
499.
Abstract

The Sefton Coast Management Scheme in northwest England uses an area‐based project to achieve coordinated land management. It is founded on the ‘'Heritage Coast'’ model pioneered by the Countryside Commission where a ‘"Project Officer”; is employed to promote the Scheme and translate the aims into practical achievement. The Sefton Coast is described and a summary of British coastal planning policy precedes a detailed analysis of the Scheme. The Scheme is assessed with reference to practical management work, its success in competition for scarce financial resources, and the involvement of volunteers. It is established that the Project Officer is crucial to the success of the Scheme and that area‐based management can best be achieved through the local government planning process. Coastal planning needs now to be reviewed at national level to develop a policy for the whole coast using the experience of projects such as the Sefton Coast Management Scheme.  相似文献   
500.
Abstract

This article explores the lack of uniform penalty assessment in the National Oceanic and Atmospheric Administration's (NOAA) civil penalty policy under the Fishery Conservation and Management Act (the Magnuson Act). The author sugests that NOAA's inconsistent penalty assessment invites noncompliance by fishers because they view the penalties as unfair and arbitrary. In particular, deterrence is undermined by the absence of a provision that removes the economic benefits of noncompliance. NOAA's policy is contrasted with the Environmental Protection Agency's (EPA) civil penalty policy, which uniformly assesses penalties while tailoring the penalty to the individual facts of the case and effectively removing the economic incentives of noncompliance. If NOAA implemented a policy similar to EPA's, NOAA would secure increased Magnuson Act compliance and higher penalty amounts.  相似文献   
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