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181.
182.
Productivity, in terms of net value added per man-year of labor and capital input, provides a more useful yardstick of airline efficiency than the widely used indices representing average unit costs or labor productivity. Large variations in productivity between airlines, in particular between U.S. and European airlines, can be explained almost entirely by differences in level of service, demand patterns and route characteristics. A regression model calibrated on 1975 data for fourteen U.S. and fourteen European scheduled airlines indicates that productivity could be increased by changes in network shape though a more liberal exchange of traffic rights, greater specialization (in particular the limited involvement of scheduled airlines in the very low yield charter market) and consumer choice — by offering higher frequency, multi-city services. 相似文献
183.
184.
Peter J.H. Shewey 《Transportation Research Part B: Methodological》1983,17(5):391-397
In order to identify route choice, registration number surveys were carried out and the numbers were then matched. Because of the nature of the routes being investigated, it was found that the level of spurious matches was large relative to the number of tripmakers. This cast considerable doubt on the estimated number of tripmakers and their mean journey times. Accordingly, it was necessary to devise an algorithm which minimised the effect of such errors. This algorithm and a method of estimating the number of residual spurious matches is discussed in this paper and is compared with the original algorithm for an actual example. 相似文献
185.
An inverse railway wagon model and its applications 总被引:1,自引:0,他引:1
Fujie Xia Colin Cole Peter Wolfs 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2007,45(6):583-605
An inverse wagon model was developed to estimate wheel-rail contact forces using only measurements of wagon body responses as inputs. The purpose of this work was to provide mathematical modelling to embed in low-cost devices that can be mounted on each freight wagon in a large wagon fleet. To minimize cost, complication, and the maintenance inconvenience of these devices, the constraint is imposed that transducers and connections are limited to locations on the wagon body. Inputs to the inverse model developed include only vertical and lateral translational accelerations and angular accelerations of roll, pitch, and yaw of the wagon body. The model combines the integration and partial modal matrix (PMM) techniques together to form an IPMM method. Besides wheel-rail contact forces some motion quantities such as the lateral and yaw displacements of wheelset are also predicted. Results from the inverse model were compared with data from full scale laboratory suspension tests for vertical suspension excitations. The inverse model was also compared with results from simulations completed in VAMPIRE® for more complicated track input profiles. The model results and the applications of the model are discussed. 相似文献
186.
Gerhard Schandl Peter Lugner Christian Benatzky Martin Kozek Anton Stribersky 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2007,45(9):835-847
In order to improve the ride comfort of lightweight railway vehicles, an active vibration reduction system using piezo-stack actuators is proposed and studied in simulations. The system consists of actuators and sensors mounted on the vehicle car body. Via a feedback control loop, the output signals of the sensors which are measuring the flexible deformation of the car body generate a bending moment, which is directly applied to the car body by the actuators. This bending moment reduces the structural vibration of the vehicle car body. Simulations have shown that a significant reduction in the vibration level is achieved. 相似文献
187.
在巴黎车展上大众展示了一款最新的高尔夫衍生车型CrossGolf,它是一款目前非常流行的混合车型,结合了SUV多种路面通过能力和MPV多功能实用性的特点。 相似文献
188.
With the increasing trend of charging for externalities and the aim of encouraging the sustainable development of the air
transport industry, there is a need to evaluate the social costs of these undesirable side effects, mainly aircraft noise
and engine emissions, for different airports. The aircraft noise and engine emissions social costs are calculated in monetary
terms for five different sized airports, ranging from hub airports to small regional airports. The number of residences within
different levels of airport noise contours and the aircraft noise classifications are the main determinants for accessing
aircraft noise social costs. The environmental impacts of aircraft engine emissions include both aircraft landing and take-off
and 30-minute cruise. The social costs of aircraft emissions vary by engine type and aircraft category, depending on the damage
caused by different engine pollutants on the human health, vegetation, materials, aquatic ecosystem and climate. The results
indicate that the relationship appears to be curvilinear between environmental costs and the traffic volume of an airport.
The results and methodology of environmental cost calculation could be applied to the proposed European wide harmonised noise
charges as well as the social cost benefit analysis of airports. 相似文献
189.
190.
Peter W. de Langen 《WMU Journal of Maritime Affairs》2008,7(1):5-16
The quality and availability of labour is important for the performance of ports. Insights from cluster theories are relevant for analysing training and education in ports, as ports can be regarded as clusters. In general, labour in clusters is relatively mobile, education services in clusters are relatively good and employees have a high willingness to invest in specific skills. However, skilled and talented labour still may be scarce, especially in regions with tight labour markets. Thus, in many clusters, including port clusters, firms and governments actively aim to improve the quality of labour. This paper presents an analysis of these efforts of firms and governments to improve the quality of the labour force in three seaport clusters. In this paper the concept of a ‘training and education regime’ is presented as an approach to analyse efforts of firms and governments to improve the quality and availability of labour. Important results of three case studies include first, the observation that the quality of training and education regime differs substantially between clusters. Second, the presence of aregime manager in Rotterdam adds to the quality of Rotterdam’s training and education regime. Such an organisation may be effective across countries and clusters. Finally, the presence ofleader firms, willing to invest in training and education also improves an education regime. 相似文献