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141.
Large North American ports are encountering serious management challenges. Surrounding communities, environmental interest groups, and government policy are focusing on protection and enhancement of public coastal amenities. In Vancouver, the federal port management system historically enabled national trade interests to override local and regional objectives at the discretion of port decison makers. In contrast, the Port of Seattle is administered at the local level, and legislation and policy require that local publics are involved in decision‐making. Recently, VPC established itself as the vanguard among Canada's major ports in the advancement of progressive management. Nevertheless, the adoption of new policies would ensure that Vancouver, and Canada's other ports, continue to be responsible leaders in Canadian coastal management. These policies include: federal, municipal, and provincial government representation on the local board of directors; strengthening community involvement; creation of a standing planning advisory committee; subjecting Canadian ports to the federal environmental assessment law; and adoption of explicit land and water use regulations.  相似文献   
142.
ATA572x系列备有三种型款,针对工业、科学和医疗(ISM)频带范围,其中ATA5723的频带范围为313-317 MHz;ATA5724为432-436 MHz:ATA5728为868-870 MHz。该系列器件的RF前端采用爱特梅尔的RF BiCMOS(即UHF6)工艺制造,并采用小型SSO20封装,因而非常适合那些应用空间非常宝贵的汽车电子应用,如遥控无匙门禁系统(RKE)和轮胎压力监测系统(TPMS)。这三种器件的引脚兼容,让系统设计人员开发一种线路布局即可应用于各种不同的解决方案。  相似文献   
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你可能会认为由于美国国内经济处于困难状态,意味着底特律的汽车制造商在2010年不会推出什么新的车型.然而,令人惊讶的是,福特和通用两大公司都将推出几款新车型,而克莱斯勒公司也会推出一款全新车型.  相似文献   
146.
A model is developed for jointly optimizing the characteristics of a rail transit route and its associated feeder bus routes in an urban corridor. The corridor demand characteristics are specified with irregular discrete distributions which can realistically represent geographic variations. The total cost (supplier plus user cost) of the integrated bus and rail network is minimized with an efficient iterative method that successively substitutes variable values obtained through classical analytic optimization. The optimized variables include rail line length, rail station spacings, bus headways, bus stop spacings, and bus route spacing. Computer programs are designed for optimization and sensitivity analysis. The sensitivity of the transit service characteristics to various travel time and cost parameters is discussed. Numerical examples are presented for integrated transit systems in which the rail and bus schedules may be coordinated.  相似文献   
147.
This research project took advantage of the implementation of a major mass transit improvement by New Jersey Transit which provided a "one-seat ride" into New York City for many commuters who previously had to transfer in Hoboken in order to take Port Authority Trans Hudson (PATH) trains into New York City. The creation of this new service provided a natural experiment in which some riders switched to the new route, while others continued to use their previous route. We studied psychological and psychophysiological responses to these commuting options, using a quasi-experimental, pre-post change, field research design.We found that riders on this new line had lower levels of stress, as multiply measured, than they had earlier, before the advent of this new train, or than did other riders currently using the Hoboken-PATH option. The stress effects seemed to be mediated by the time of the trip – that is, the reduced trip time of the new, direct service seemed to be a primary factor in the reduced stress to riders. Predictability of the trip was also inversely correlated with stress, but did not distinguish between the commuter groups. These results were largely replicated with a student group who rode the same lines acting as simulated commuters.  相似文献   
148.
As demand increases over time, new links or improvements in existing links may be considered for increasing a network's capacity. The selection and timing of improvement projects is an especially challenging problem when the benefits or costs of those projects are interdependent. Most existing models neglect the interdependence of projects and their impacts during intermediate periods of a planning horizon, thus failing to identify the optimal improvement program. A multiperiod network design model is proposed to select the best combination of improvement projects and schedules. This model requires the evaluation of numerous network improvement alternatives in several time periods. To facilitate efficient solution methods for the network design model, an artificial neural network approach is proposed for estimating total travel times corresponding to various project selection and scheduling decisions. Efficient procedures for preparing an appropriate training data set and an artificial neural network for this application are discussed. The Calvert County highway system in southern Maryland is used to illustrate these procedures and the resulting performance.  相似文献   
149.
The disadvantages of conventional transportation study models, in particular their large data requirements and their weaknesses in dealing with changes in trip generation rates have led to a need for a simple model that can quickly and at low cost examine alternative public transport strategies.This paper investigates simple economic models of bus demand, examines alternative variables that can be used and discusses some alternative model forms. It demonstrates the results of a model using data from twelve urban bus operators in Britain and compares the results with those from other types of study. The model utilises fare and service quality elasticities to explain the decline in passengers on urban bus services, and derives an average elasticity with respect to fare changes of –0.31 and with respect to service quality changes of +0.62. It is estimated that fare rises accounted for 13% of the 43% decline in passengers over the last fifteen years, vehicle mileage reductions for 14.3% and that only 15.7% was due to such factors as rising car ownership which are often given as the cause of declining bus patronage.The results, by showing that passengers are far more sensitive to changes in service than they are to fare rises, are a useful guide to the broader public transport policy issues, and the paper concludes that the model does provide a useful method of forecasting public transport demand at a strategic level. Further work is needed, however, to establish more accurate forecasts for different types of passenger and studies are now being undertaken to establish these and to construct an operational forecasting model that can be applied with only limited data requirements  相似文献   
150.
This paper presents a method with which one can evaluate alternative platooning control strategies with respect to worst case behavior. The motivation is to provide platoon control designers with an objective means of evaluating robustness in the face of system uncertainties. The approach can be viewed as an extension of optimal control procedures and is applicable to complex, nonlinear systems. An arbitrary number of uncertain parameters, unmodeled components and inputs are allowed. The end result is a lower bound for the worst case platoon performance.  相似文献   
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