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71.
Accurate measurement of travel behaviour is vital for transport planning, modelling, public health epidemiology, and assessing the impact of travel interventions. Self-reported diaries and questionnaires are traditionally used as measurement tools; advances in Global Positioning Systems (GPS) technology allow for comparison. This review aimed to identify and report about studies comparing self-reported and GPS-measured journey durations. We systematically searched, appraised, and analysed published and unpublished articles from electronic databases, reference lists, bibliographies, and websites up to December 2012. Included studies used GPS and self-report to investigate trip duration. The average trip duration from each measure was compared and an aggregated, pooled estimate of the difference, weighted by number of trips, was calculated. We found 12 results from eight eligible studies. All studies showed self-reported journey times were greater than GPS-measured times. The difference between self-report and GPS times ranged from over-reporting of +2.2 to +13.5 minutes per journey. The aggregated, pooled estimate of the difference, weighted by number of trips, was over-report of +4.4 minutes (+28.6%). Studies comparing self-reported and GPS-measured journey duration have shown self-reported to be consistently over-reported across the study sample. Our findings suggest that when using self-reported journey behaviour, the journey durations should be treated as an over-estimation. 相似文献
72.
Vaubel Ulrich Barsness Richard W. Saltzman Arthur Haight Frank Prestwood Smith Paul Brown Peter 《Transportation》1974,3(2):185-192
73.
74.
This paper discusses the development of a system model for the wireless steering wheel angle sensor and steering wheel system
for the evaluation of the steer by wire system in a vehicle dynamic system. The steering wheel sensor is a wireless, contact-less
sensor utilizing an optical medium for angle detection. The optical medium is operated based on a photodiode and photo-detector
head. A reflecting disc or code-wheel, working similar to a compact disc, is used to reflect the light from the photodiode
back to the photo-detector. The beam is reflected based on the content in the reflective disc to measure the relative angle
through a micro-controller. The proposed wireless steering sensor and steer by wire system is modeled using the Matlab/Simulink
and their performance is investigated to evaluate the steering response, vehicle dynamics, and steering feel of the system.
Finally, the feasibility of the proposed system is discussed based on the developed model and simulation results. 相似文献
75.
Among dispatching control approaches, the holding option has attracted the most attention in bus control. However, holding a vehicle at a transfer station may exacerbate the delays because more passengers might accumulate at downstream stations and may also affect other connecting routes at other transfer stations. Our problem is to minimize the total costs of dispatching ready vehicles at each transfer station along coordinated routes in a multi‐hub transit network. The total costs include the waiting cost for on‐board passengers, the missed connection costs for late arrival passengers at the subject transfer station and possible transfer costs at downstream transfer stations. We develop a heuristic algorithm to optimize the holding times based on real time information about late vehicles. The results show that ready vehicles should be held longer when the arrival variances of late vehicles are small or when many late connecting passengers are expected. 相似文献
76.
Ye Tian Sheng Liu William J.T. Daniel Paul A. Meehan 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2015,53(5):692-709
This paper presents the locomotive traction controller performance with respect to the track wear under different operation conditions. In particular, an investigation into the dynamic response of a locomotive under changing wheel–rail friction conditions is performed with an aim to determine the effect of controller setting on track wear. Simulation using a full-scale longitudinal–vertical locomotive dynamic model shows that the appropriately designed creep threshold, controller, settings can effectively maintain a high tractive effort while avoiding excessive rail damage due to wear, especially during acceleration under low speed. 相似文献
77.
Paul White 《商用汽车》2014,(1)
正凭着C和K系列工程车,雷诺卡车为用户提供了设计良好、并通过严格测试的产品;这不仅仅意味着能做到在公路和非公路上驾驶,还代表着更高的舒适性和驾驶性能。2013年,雷诺卡车新系列车型的发布无疑是卡车界的一件盛事。新车难以置信的独特颜色和造型设计成为卡车爱好者们很长时间内的谈资;也许除了"高迪Style"(来自西班牙加泰罗尼亚的著名建 相似文献
78.
This paper investigates the length scale of ocean surface breaking waves in the spectral range of intermediate wavelength components a few centimeters to a few meters long. The spectral properties of wave breaking are examined first with the dissipation function of the wave action density conservation equation. The analysis reveals a strong breaking signature in wave components between 0.15 and 1.5 m long in the form of a quasi-singular behavior of the dissipation function using the present formulation of the wind-generation and breaking dissipation functions. Independent studies of more-direct breaking observations of radar tracking of sea spikes in the past have shown close correlation between sea spikes and scatterers traveling at the speed of surface waves a few meters long and much shorter than the dominant wavelength. This feature of sea-spike properties is consistent with the breaking signature of the dissipation function in similar wavelengths. The intermediate-scale waves are the primary contributor of the ocean surface mean-square slope. The close correlation between the gas transfer rate and the mean-square slope has been demonstrated repeatedly. A better understanding of the wave dynamics of intermediate-scale waves is important for clarification of various gas transfer mechanisms. 相似文献
79.
James H. Stone Leonard M. Bahr Jr. John W. Day Jr. R. Eugene Turner Paul H. Templet 《Coastal management》2013,41(1):9-35
Abstract Preliminary management guidelines have been derived for oil and gas activities in coastal Louisiana. Derivation of these guidelines was done in terms of the natural function of the coastal ecosystem; this means that all economic activities should be designed to complement natural function as much as possible. The guidelines range in scope from very specific, almost performance standards, to very general admonitions. For example, we have suggested that spoil banks, produced as a result of dredging, should not be higher than the height of the daily tide or roughly 15 cm in coastal Louisiana, and at the other extreme, we have suggested that all dredging should be done with great care during wildlife migrations, spawning, and nesting times. 相似文献
80.
Jonathan D. Phillips 《Coastal management》2013,41(4):439-449
Abstract A watershed‐based approach to water quality management is necessary for protecting coastal water quality, but the relative importance of inland pollution sources on estuaries is often overestimated. This can lead to a misallocation of coastal water protection resources and ignorance of coastal zone pollution sources. This overestimation of upstream contributions is attributable to a failure to recognize that many estuaries have little or no inland drainage area, the confusion of basinwide pollutant loading with pollutant delivery to estuaries, the low delivery ratios for many pollutants within drainage basins, and disproportionately high pollutant delivery for sources within the coastal zone. Examples are given from North Carolina. As a general rule, resources expended on pollution control within or near the coastal zone will result in more coastal water quality improvement per unit effort than resources expended upstream. 相似文献