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991.
用格子Boltzmann方法中的伪势模型对两个液滴的合并过程进行了数值模拟。详细研究了两液滴能否合并临界尺寸和液滴合并过程中液桥的形成与演化的关系,并研究了表面张力对合并速度的影响。研究结果发现当两个液滴之间距离小于2倍界面厚度时,两个液滴在不受外力的作用下能够自动合并;液桥的宽度与演化时间有一定的指数关系;表面张力越大,合并速度越快,这个结果与前人的理论预测和实验结果一致。 相似文献
992.
The aerodynamic characteristics of wind turbines are closely related to the geometry of their blade profiles. The innovation and the technological development of wind turbine blade profiles can be centred on two tendencies. The first is to improve the shape of the existing airfoils and the second is to design new shapes of airfoils in order to get some more ambitious aerodynamic characteristics and enhanced performance.The aim of this paper is to develop an accurate airfoil analysis lower order code, based on the singularities method, for wind turbine applications. The 2D incompressible potential flow model has been used. In the implementation of the singularities method, source–vortex distributions over the airfoil contour are used to compute the flow characteristics. The accuracy and the validity of the results have been tested using experimental data obtained from Wind Turbine Airfoil Catalogue “Risø National Laboratory, Roskilde, Denmark, August 2001” and have shown considerable agreement. 相似文献
993.
Yoshimitsu Uemura Takami Kai Rintarou Natori Takeshige Takahashi Yasuo Hatate Masahiro Yoshida 《Renewable Energy》2004,29(4):581
A study was carried out to see if the potential of renewable energy sources other than hy droelectric power, such as wind, photovoltaic, solar thermal, biomass and waste energy sources, can meet the current energy consumption in Yakushima. The current electricity consumption can be covered by wind and photovoltaic energy sources. The total potential of wind and photovoltaic energy sources is 5.4 times as much as the current electricity consumption. LP gas and kerosene can be replaced by solar thermal and biogas energy. The potential of plant biomass and municipal waste is not sufficient (approximately one third) to cover the rest of the fossil fuels (gasoline, diesel oil and heavy oil). Also, plant biomass and municipal waste must be converted into fluid form. This shortage can be covered by the po tential of wind and photovoltaic energy sources. We also investigated the possibility of tourism expansion using the potential of wind and photovoltaic energy sources. Taking into account three types of capacity (energy, accommodation and transportation), Yakushima can accept approximately four times as many tourists as the current number of tourists. 相似文献
994.
双PWM变频调速系统采用交一直一交拓扑结构,通过可控整流,实现网侧电流接近正弦波,网侧功率因数近似为1,具有较快的动态响应,双向传输电能等诸多优点,实现了节能调速。针对NPC型三电平拓扑给出了一种参考电压分解的三电平SVPWM算法,简化为两电平SVPWM算法,比传统的三电平SVPWM算法易于实现,仿真验证7该算法的有效... 相似文献
995.
996.
Membrane-based processes are becoming increasingly important in the field of industrial gas separation. Such processes are attractive from the standpoint of high separation selectivity and high conversion ratios in cases involving gas phase and gas–solid reactions. In particular, the application of dense ceramic mixed ionic and electronic conducting membranes to separate gases such as oxygen through ambipolar transport of oxygen ions and electrons and hydrogen through ambipolar transport of protons and electrons from gas mixtures at elevated temperatures (>500°C) is gaining increasing importance. As a specific example, the requirement of high-purity tonnage hydrogen with less than 10 ppm carbon monoxide impurity levels would be absolutely essential for low-temperature proton exchange membrane fuel cells to gain wide market acceptance. We analyze herein a novel membrane-based hydrogen separation process which has heretofore not been widely reported in the literature. 相似文献
997.
王耕 《电子产品可靠性与环境试验》2011,29(2):7-12
对接地的概念、技术要求和接地的目的进行了详细的阐述,通过由接地极流人大地的电流,以接地极之间的相干性为例,详细分析了地电位变化的成因.根据大功率广播发射机的运行情况,从发射机的接地、天馈线接地、电缆屏蔽层接地及接地点的选取等多方面研究了电子设备应对地电位变化的措施. 相似文献
998.
999.
Based on current voltage (I-Vg) and capacitance voltage (C-Vg) measurements, a reliable procedure is proposed to determine the effective surface potential Vd.Vg/ in Schottky diodes. In the framework of thermionic emission, our analysis includes both the effect of the series resistance and the ideality factor, even voltage dependent. This technique is applied to n-type indium phosphide (n-InP) Schottky diodes with and without an interfacial layer and allows us to provide an interpretation of the observed peak on the C-Vg measurements. The study clearly shows that the depletion width and the flat band barrier height deduced from C-Vg, which are important parameters directly related to the surface potential in the semiconductor, should be estimated within our approach to obtain more reliable information. 相似文献
1000.
N. Oyama Y. TakanashiS. Kaneko K. MomiyamaK. Suzuki F. Hirose 《Microelectronic Engineering》2011,88(9):2959-2963
The forward and reverse current density-voltage (J-V) and capacitance-voltage (C-V) characteristics of pentacene/n−-silicon heterojunction diodes were investigated to clarify the carrier conduction mechanism at the organic/inorganic heterojunction. Current rectification characteristics of the pentacene/n−-Si junctions can be explained by a Schottky diode model with an interfacial layer. The diode parameters such as Schottky barrier height and ideality factor were estimated to be 0.79-1.0 eV and 2.4-2.7, respectively. The C-V analysis suggests that the depletion layer appears selectively in the n−-Si layer with a thickness of 1.47 μm from the junction with zero bias and the diffusion potential was estimated at 0.30 eV at the open-circuit condition. The present heterojunction allows the photovoltaic operation with power conversion efficiencies up to 0.044% with a simulated solar light exposure of 100 mW/cm2. 相似文献