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131.
This paper presents a novel method to evaluate the characteristics of the spherical hydrostatic supporting system for the floated inertial platform in dynamic environments. This hydrostatic supporting system consists of eight suspension pads fixed on the inner sphere. The force model for each single suspension pad is established. The dynamic equations for the inner sphere are also derived from the geometrical configuration. The stable time and stable deviation of the inner sphere in different dynamic environments are calculated. The results show that the hydrostatic supporting system can make the inner sphere resistant to the vehicle acceleration effectively and omnidirectionally. 相似文献
132.
在分析磁流变减振器的结构与原理的基础上,建立起较为简化的汽车磁流变减振器数学模型。同时,建立了1/4汽车半主动悬架系统动力学模型及路面谱模型;分别设计了基于磁流变半主动悬架系统的天棚控制器、地棚控制器、PID控制器及模糊控制器,并利用Matlab/Simulink软件进行了仿真试验对比研究。在天棚控制策略下,车身加速度降低16.32%,悬架动挠度降低16.91%;在地棚控制下,车身加速度降低11.29%,悬架动挠度降低2.94%;在PID控制下,车身加速度降低79%,悬架动挠度反而上升73%;在模糊控制下,车身加速度降低21%,悬架动挠度降低12%,轮胎动载荷降低5%。结果表明,模糊控制磁流变半主动悬架有效减小了车身加速度、悬架动挠度、轮胎动载荷,明显地提高了汽车乘坐舒适性和操纵稳定性。 相似文献
133.
In response to technical issues such as the ineffective noise reduction impact of balanced cage and single-seat control valves, the U-shaped noise reduction cage control valve is investigated and developed. In addition, its equal percentage flow properties and noise reduction impact are good, allowing it to effectively minimize the noise created by the change of fluid parameters of medium such as vapor, gas, and gas-liquid two-phase flow. The flow coefficient and flow properties were analyzed. The noise features of the medium air flow at small and large openings of 30% and 85% are simulated and analyzed, respectively. The pressure, velocity, and temperature of the inlet and outlet air, as well as the sound intensity maximum and sound power level maximum, are also analyzed with the opening curves. A small opening of 30% was selected, and the noise characteristics of cavitation generated by the medium water flow were simulated and analyzed. Together with the pressure and temperature change curves of the incoming water, the volume maxima and density minima of water are studied. The maximum sound intensity and sound power level of water are analyzed using the pressure and temperature curves of inlet water, as well as the cavitation coefficient and the degree of opening. The results of the trial for the pressure resistance of the valve body and the trial for the valve seat seal indicate that both the valve body strength and the valve seat seal meet the specifications. Comparing the noise trial results and simulation results reveals that the sound intensity and sound power level assessed by the trial and simulation are comparable, and the noise reduction impact of the control valve is positive. 相似文献
134.
模拟体液法合成晶须状类骨纳米羟基磷灰石的研究 总被引:5,自引:0,他引:5
通过增加模拟体液中钙盐和磷盐的浓度,在模拟体液中合成了晶须状类骨纳米羟基磷灰石(HAp)粉体。利用X射线衍射(XRD)和红外吸收光谱(FTIR)分析粉体的物相组成和基本特征,利用透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)观察晶须的形貌、尺寸与生长方向,将粉体在500~900℃不同温度下热处理,研究其热稳定性。结果表明,晶须状羟基磷灰石的平均长径比为25:1(长100nm,直径4nm),晶须沿c轴方向生长;热处理温度超过700℃,羟基磷灰石易发生分解。 相似文献
135.
针对渤海油田疏松砂岩油藏油层厚度大、非均质性严重、酸化后含水率上升的问题,开展了乳化柴油封堵分流能力实验研究。物理模拟实验表明,以油水体积比3∶7制备的乳化柴油体系具有选择性封堵高渗透层,对低渗油层的封堵能力较弱。应用该体系后可有效将后续液体分流到低渗层,且对高渗水层的渗透率有较大幅度降
低,而对低渗油相渗透率影响很小。与常规酸化解堵措施相结合,可起到均匀酸化与控水增产的目的。 相似文献
136.
137.
138.
Dipl.‐Ing. H. Marschall Dipl.‐Ing. R. Mornhinweg Dipl.‐Ing. A. Kossmann Dipl.‐Ing. S. Oberhauser Dipl.‐Ing. K. Langbein Prof. Dr.‐Ing. O. Hinrichsen 《化学,工程师,技术》2010,82(12):2141-2149
The design of industrial gas/liquid reactors such as bubble columns requires detailed information with respect to the flow structure and characteristics of two‐ or multiphase systems in the reactor. The contribution is focused on the evaluation of the simulation results obtained by a selection of models. The results are further compared with those reported in literature. The simulations have been performed with the CFD software OpenFOAM®. The main focus of the numerical simulation was set on capturing the characteristic process and design parameters of bubble columns. 相似文献
139.
以液压系统的液压压力、流量和功率为参量,借鉴欧姆定律提出“液阻”概念,并以此初步归纳了各种“导流”液压元器件的“液阻”共性.藉此各种液压元器件所共有的“液阻”属性,探讨了面向液压系统的数学运算及分析评估的可行性. 相似文献
140.
《International Heat Treatment & Surface Engineering》2013,7(2):79-84
AbstractNew technologies for fluidised bed nitrocarburising are described that employ either a chemically active bed or a chemically inert bed, plus additional activation of the fluid bed with mechanical vibration (alone or accompanied by the flow of a gas medium). Investigations were performed on X160CrMoV121 tool steel, with three methods of nitrocarburisation, at 580°C for 2 and 4 h. The nitrocarburised layers produced were investigated via surface hardness tests and microhardness distribution examination, metallography and X-ray spectrometry. Wear results are also reported. The new processes are reported to reduce gas consumption and to provide better case properties under optimised process conditions. 相似文献