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991.
992.
Ioanna E. Manataki Konstantinos G. Zografos 《Transportation Research Part C: Emerging Technologies》2009,17(4):428-443
Decision making for airport terminal planning, design and operations is a challenging task, since it should consider significant trade-offs regarding alternative operational policies and physical terminal layout concepts. Existing models and tools for airport terminal analysis and performance assessment are too specific (i.e., models of specific airports) or general simulation platforms that require substantial airport modelling effort. In addition, they are either too detailed (i.e., microscopic) or too aggregate (i.e., macroscopic), affecting, respectively, the flexibility of the model to adapt to any airport and the level of accuracy of the results obtained. Therefore, there is a need for a generic decision support tool that will incorporate sufficient level of detail for assessing airport terminal performance. To bridge this gap, a mesoscopic model for airport terminal performance analysis has been developed, that strikes a balance between flexibility and realistic results, adopting a system dynamics approach. The proposed model has a modular architecture and interface, enabling quick and easy model building and providing the capability of being adaptable to the configuration and operational characteristics of a wide spectrum of airport terminals in a user-friendly manner. The capabilities of the proposed model have been demonstrated through the analysis of the Athens International Airport terminal. 相似文献
993.
更安全 更舒适 更环保 犹如宝马3系之于入门级豪华车,在中大型车这一细分市场.奔驰E级轿车是当之无愧的标杆,无需赘言,超过1200万辆的历史总销量就是最好的佐证。2009年,我们迎来了仿佛从2046年穿越时空回来的全新一代E级轿车,其智能程度之高让人咋舌,通过一系列独特的驾驶辅助功能.提升了安全性。 相似文献
994.
After 1975, the appearance of finite element numerical limit method and the application and development of computer technology have brought the elastic-plastic analytical calculation of engineering materials into a new era of numerical limit calculation. The new methods, namely, strength reduction method and load increment method, as well as the recently proposed ultimate strain method, are adopted in the rock tunnels studied in this paper. To solve the uncertainty of mechanical parameters of surrounding rock in rock tunnels and provide more scientific and reasonable mechanical parameters of surrounding rock, the surrounding rock classification must be made combining theory, investigation and experience. Taking the surrounding rock classification in rail transit tunnels as an example, the improvement of the classification level includes improving the strength index, mainly adopting the quantitative classification method, reasonably determining the basic index BQ value of rock mass quality, increasing the number of surrounding rock classifications, formulating the surrounding rock classification tables for the running tunnel and the station tunnel, and achieving the coordination and unification of qualitative and quantitative classification methods. Finally, the quantitative indexes of surrounding rock self-stability are determined, and the more scientific and reasonable physical and mechanical parameters of surrounding rocks are put forward through back calculation. © 2022, Editorial Office of "Modern Tunnelling Technology". All right reserved. 相似文献
995.
The study aimed to test the utility of instruments deployed on marine mammals for measuring physical oceanographic variation and, using this method, to examine temperature variation in the coastal waters around South Georgia. There was a significant correlation between temperature measurements made using a towed undulating oceanographic recorder (UOR) and concurrent measurements from time-depth recorders (TDRs) fitted to lactating Antarctic fur seals foraging from the coast of South Georgia. Congruence was found at horizontal spatial scales from 0.01°×0.01° to 0.5°×0.5° (degrees of latitude and longitude), and at a vertical scale of 10 m. However, there was no significant correlation between temperature measured by TDRs in the top 5 m and sea surface temperature (SST) measured by satellite remote sensing. TDR data provided information about temperature variation vertically through the water column, and through time. The UOR data were used to recalibrate the TDR data in order to correct for the slow response time of the TDR thermistor relative to the speed of seal movements through the water column. Seasonal temperature variation was apparent, and temperatures also varied between regions, and with bathymetry. These results were consistent with the current interpretation of the coastal oceanography around South Georgia. In particular, the relationship between on- and off-shelf waters showed larger amounts of warmer surface water in a region in which more run-off was to be expected. The study also showed that Antarctic fur seals concentrate their activity in regions of colder, and presumably oceanic, water. Such instrumented animals could provide near real time data for assimilation into ocean models. 相似文献
996.
E. Chevallier A. Can M. Nadji L. Leclercq 《Transportation Research Part D: Transport and Environment》2009,14(2):100-110
Three families of road noise prediction models can be distinguished. Static noise models only consider free-flow constant-speed traffic with uniformly distributed vehicles. Analytic noise models assume that all vehicles are isolated from one another but account for their mean kinematic profile over the network. Micro-simulation noise models relax the hypothesis of no interaction between vehicles and fully capture traffic flow dynamic effects such as queue evolution. This study compares the noise levels obtained by these three methodologies at signalized intersections and roundabouts. It reveals that micro-simulation noise models outperform the other approaches. Particularly, they are able to capture the effects of stochastic transient queues in under-saturated conditions as well as stop-and-go behaviors in oversaturated regime. Accounting for traffic dynamics is also shown to improve predictions of noise variations due to different junction layouts. In this paper, a roundabout is found to induce a 2.5 dB(A) noise reduction compared to a signalized intersection in under-saturated conditions while the acoustic contributions of both kinds of junctions balance in oversaturated regime. 相似文献
997.
W. Daves F. D. Fischer 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2008,46(1):71-83
A hierarchical concept for describing the rolling/sliding contact of a wheel on a rail is proposed, which is developed to model the near surface deformation of the contacting partners depending on the vehicle system dynamics. In principal the vehicle dynamics simulation delivers the input for a static finite element model for the elastic-plastic rolling/sliding contact investigation. To include also more realistic rough surfaces in the calculations, which is absolutely necessary to predict the highly deformed surface layer as observed in wheels and rails, a further refinement of the mesh is necessary and performed. The output values of the static finite element model are now boundary conditions for the finite element micro-model. The results of this micro-model correspond well with the micro-structural investigations of wheel and rail surfaces. 相似文献
998.
Among the general problematic of the HEV power trains, the most critical point is the determination of the power-split ratio
between the mechanical and the electrical paths, known as the energy management strategy (EMS). Many EMS are proposed in the
literature, and can be grouped in two categories: the local optimization EMS and the global optimization EMS. The local optimization
category corresponds to the EMS based on human expertise and the knowledge of the power train components efficiency maps.
Thus, the local optimization EMS manages the power train operations by referring to predefined rules. The drawback of such
strategies is that it brings an instantaneous fuel consumption optimization, and does not fully optimize the fuel consumption
over the whole trip. Therefore, additional fuel savings are still possible. This paper presents an overall optimized predictive
EMS for the Toyota Hybrid System (THS-II) power train of the Prius. The proposed EMS is based on Dynamic Programming (DP),
where the prior knowledge of the route is required in order to predetermine the power-split ratio and optimize the fuel consumption
for the whole predicted route. The DP EMS proposed for the THS-II power train is designed with a very short computation time,
intended to be implemented in real-time applications. The potential of this DP-controller in reducing fuel consumption on
regulatory cycles are computed and compared to a rule-based controller and to the Prius published fuel consumption results.
Finally, the fuel reduction enhancements of the DP-controller are computed for real road tests achieved on a MY06 Prius in
Ile-de-France, by comparing to the associated observed consumption measurements. 相似文献
999.
Two versions of an optimal network design problem with shipments proportional to transportation costs are formulated. Extensions of an algorithm developed in prior research for solving these problems are proposed and tested. The performance of the algorithms is found to improve substantially as the dependence of shipments on costs is increased. Moreover, the optimal solutions obtained are unexpectedly robust with respect to a wide range of transportation cost assumptions. These findings could have important computational and policy implications if applicable to larger networks. 相似文献
1000.