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911.
An identity-based encryption(IBE) was studied with non-interactively opening property that the plain text of a ciphertext can be revealed without affecting the security of the encryption system.Two kinds of non-interactive opening properties for IBE schemes were defined along with a concrete scheme in each case. 相似文献
912.
A high-performance, low cost inverse integer transform architecture for advanced video standard (AVS) video coding standard was presented. An 8×8 inverse integer transform is required in AVS video system which is compute-intensive. A hardware transform is inevitable to compute the transform for the real-time ap-plication. Compared with the 4×4 transform for H.264/AVC, the 8×8 integer transform is much more complex and the coefficient in the inverse transform matrix Ts is not inerratic as that in H.264/AVC. Dividing the Ts into matrix S8 and R8, the proposed architecture is implemented with the adders and the specific CSA-trees instead of multipliers, which are area and time consuming. The architecture obtains the data processing rate up to 8 pixels per-cycle at a low cost of area. Synthesized to TSMC 0.18 μm COMS process, the architecture attains the operating frequency of 300 MHz at cost of 34 252 gates with a 2-stage pipeline scheme. A reusable scheme is also introduced for the area optimization, which results in the operating frequency of 143 MHz at cost of only 19 758 gates. 相似文献
913.
A real time assimilation and forecasting system for coastal currents is presented. The purpose of the system is to deliver current analyses and forecasts on based on assimilation of high-frequency radar surface current measurements. The local Vessel Traffic Service monitoring the ship traffic to two oil terminals on the coast of Norway received the analyses and forecasts in real time.A new assimilation method based on optimal interpolation is presented where spatial covariances derived from an ocean model are used instead of simplified mathematical formulations. An array of high frequency radar antennae provides the current measurements. A suite of nested ocean models comprises the model system. The observing system is found to yield good analyses and short range forecasts that are significantly improved compared to a model twin without assimilation. The system is fast, analysis and 6-h forecasts are ready at the Vessel Traffic Service 45 min after acquisition of radar measurements. 相似文献
914.
915.
基于公钥基础结构PKI,利用现有的军事网络,改进战时CA遭到破坏时的体系方案和密钥实时更换部分,建立一种适用于军事用途的架构。 相似文献
916.
A study of the Alboran sea mesoscale system by means of empirical orthogonal function decomposition of satellite data 总被引:1,自引:0,他引:1
A. Baldacci G. Corsini R. Grasso G. Manzella J. T. Allen P. Cipollini T. H. Guymer H. M. Snaith 《Journal of Marine Systems》2001,29(1-4)
This paper presents the results of a combined empirical orthogonal function (EOF) analysis of Advanced Very High Resolution Radiometer (AVHRR) sea surface temperature (SST) data and sea-viewing wide field-of-view sensor (SeaWiFS) chlorophyll concentration data over the Alboran Sea (Western Mediterranean), covering a period of 1 year (November 1997–October 1998). The aim of this study is to go beyond the limited temporal extent of available in situ measurements by inferring the temporal and spatial variability of the Alboran Gyre system from long temporal series of satellite observations, in order to gain insight on the interactions between the circulation and the biological activity in the system. In this context, EOF decomposition permits concise and synoptic representation of the effects of physical and biological phenomena traced by SST and chlorophyll concentration. Thus, it is possible to focus the analysis on the most significant phenomena and to understand better the complex interactions between physics and biology at the mesoscale. The results of the EOF analysis of AVHRR-SST and SeaWiFS-chlorophyll concentration data are presented and discussed in detail. These improve and complement the knowledge acquired during the in situ observational campaigns of the MAST-III Observations and Modelling of Eddy scale Geostrophic and Ageostrophic motion (OMEGA) Project. 相似文献
917.
H型截面吊杆气动性能的风洞试验 总被引:7,自引:2,他引:5
通过节段的静力和弹簧悬挂动力试验,对H型吊杆的驰振和涡激振动性能进行分析。不做任何措施的H型吊杆在一定的风速下很容易发生驰振。腹板开孔的H型吊杆在横桥向来流时表现出涡激振动,开孔越大,涡激振动的振幅越小,方形孔比圆形孔要小,表明腹板开孔可以抑制该风向的涡激振动。在接近顺桥向来流的作用下,实腹和只在腹板开孔的吊杆在风速不高时表现为弛振。在翼板上加风嘴时,没有发现驰振,但横桥向来流时的涡激振动有较大增加。翼板上开孔能提高吊杆顺桥向来流的驰振临界风速,甚至杜绝该方向驰振的发生,且开孔越大效果越好。 相似文献
918.
从多方视角介绍了日产汽车公司美国坎顿工厂的建设背景和投产情况,简要概括了坎顿工厂所采取的提高劳动生产率的生产集中化战略。 相似文献
919.
双线铁路列车运行调整的禁忌搜索算法 总被引:8,自引:2,他引:6
关于列车运行调整(TOA)的优化模型和算法,国内外专家学者提出的具有代表性的主要算法可分为仿真方法、运筹学方法和人工智能方法。TOA问题具有约束性强、优化指标众多、动态性、实时性、组合优化特性等特点。因此结合目前铁路运输工作组织实际,以列车晚点率最小为优化目标,通过在可行解空间内部搜索待调整列车最优铺画顺序的方法求解TOA问题。建立了基于混合0-1线性规划模型的双线铁路列车运行调整的优化模型,提出了采用禁忌搜索算法搜索列车优化铺画顺序的方法。经在京广线、京沪线部分区段投入实际应用,验证了模型及算法的有效性和可靠性。 相似文献
920.
绕船体自由表面流的数值模拟 总被引:16,自引:3,他引:13
本文采用RANS方程和VOF算法数值模拟了系列60粘性自由面流动,比较了幂指数律,二阶迎风,QUICK格式对计算结果的影响,详细给出了波形,阻力,伴流等的计算结果,与试验及其它计算结果比较显示本文的计算方法具有较好的计算精度,可用于船型性能分析和优化。 相似文献