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31.
Alan L. Porter 《Transportation》1981,10(1):3-22
Federal funding strategies greatly affect investment in urban transportation facilities in the United States. This analysis concentrates on the implications of varying federal aid matching requirements, structuring aid programs as categorical or block grants, and allo cating funds on a discretionary basis or according to formula. Toward this end the effects of recent federal transit aid arrangements are assessed.Increased federal matching share broadens program participation, especially among smaller cities. However, when offered a choice, communities' preference for more generous federal aid shares is tempered by their election of discretionary grants (e.g., Urban Mass Transportation Administration - UMTA - Section 3) instead of drawing on formula funds (e.g., UMTA Section 5 or highway fund transfers). Formula funds are easier to administer, distributed quite evenly in the UMTA case, and generally more suitable than discretionary funds except where expenditures are large relative to budgets. Categorical aid programs shift local priorities, and thus should be used with cautionOverall, results suggest that one must begin with established transportation objectives against which to evaluate the effectiveness of funding arrangements. In particular, it is critical to make clear the rationale for federal involvement in funding specific programs. Four such federal funding intents are distinguished: compelling national interest, regional development, stimulation of recipient investment in the given program, or financial relief for the aid recipient. Conclusions are drawn as to the desirability of various funding policies according to such program intent. 相似文献
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Abstract This paper models trip generation for a cross-section of residential developments around the UK. Consistent with recent literature, the empirical model tests whether trip making patterns for residential developments are independent of car ownership and finds that trip generation is dependent upon car ownership socio-economic factors and site-specific characteristics, in particular land-zone type (e.g. town centre, out of town, etc.). However, public transport services are not found to have a significant relationship with trip generation; consequently, a policy implication of the results is that increasing bus services to residential developments is not associated with a reduction in generated trips. 相似文献
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Vassilis Kitidis Louise Tizzard Günther Uher Alan Judd Rob C. Upstill-Goddard Ian M. Head Neil D. Gray Gillian Taylor Ruth Durn Raquel Diez Jorge Iglesias Soledad García-Gil 《Journal of Marine Systems》2007,66(1-4):258
Methane (CH4) concentrations were measured in the water column, in sediment porewaters, and in atmospheric air, in the Ría de Vigo, NW Spain, during both the onset (April 2003) and at the end of (September 2004) seasonal upwelling. In addition, CH4 concentration and stable isotopic signatures (δ13CH4) were measured in porewaters, and sediment methanogenesis and aerobic oxidation of CH4 were determined in sediment incubations. Surface water column CH4 (2 m depth) was in the range 3–180 nmol l− 1 (110–8500% saturation) and followed a generally landward increase but with localised maxima in both the inner and middle Ría. These maxima were consistent with CH4 inputs from underlying porewaters in which CH4 concentrations were up to 3 orders of magnitude higher (maximum 350 μmol l− 1). Surface water CH4 concentrations were approximately three times higher in September than in April, consistent with a significant benthic CH4 flux driven by enhanced sediment methanogenesis following the summer productivity maximum. CH4 and δ13CH4 in sediment porewaters and in incubated sediment slurries (20 °C) revealed significant sediment CH4 oxidation, with an apparent isotopic fractionation factor (rc) of 1.004. Using turbulent diffusion models of air–sea exchange we estimate an annual emission of atmospheric CH4 from the Ría de Vigo of 18–44 × 106 g (1.1–2.7 × 106 mol). This estimate is approximately 1–2 orders of magnitude lower than a previous estimate based on a bubble transport model. 相似文献
34.
The hatchcoveless container ship is an innovative design which improves cargo handling productivity. The paper develops a methodology for measuring the gains. To illustrate the impact of faster port times on voyage profitability a voyage cost analysis is used to show its operational advantages. An investment analysis demonstrates the value which will accrue to the company over the life of the vessel. 相似文献
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Alan J. Horowitz 《运输规划与技术》2013,36(3):175-182
Maximum time lengths of urban trips can be used to calculate major user benefits of transportation improvements. These benefits include those associated with reduced cost of travel, those associated with travel to additional destinations, and those associated with improved quality of destinations. Maximum trip lengths can be measured using techniques of psychological scaling. 相似文献
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David C. Broadstock Alan Collins 《Transportation Research Part A: Policy and Practice》2010,44(4):195-200
This study presents a means of determining a historic (generalised cost based) price index for cycling in the UK for the period 1949–2006 using annual demand data. By specifying demand as a function of generalised price and income and then applying a structural time-series model to elucidate the unobserved component of prices (while controlling for observed income levels), it is illustrated that the role of prices in influencing demand is non-trivial. Over the sample period price responses generally influence demand for cycling to a greater extent than income effects. 相似文献