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101.
Theoretical results, based on perturbation techniques, are presented for fully developed, both hydrodynamically and thermally, forced convection in both parallel plate and circular microchannels subject to isoflux wall boundary condition. Scaling effects, including variable property, viscous dissipation, velocity slip, and temperature jump, are studied for flow of both gases and liquids. The interactions between the aforementioned effects, due to temperature-dependence of the fluid properties that couples the momentum and thermal energy equation, are also examined in detail. 相似文献
102.
针对云计算服务环境下软硬件节能和负载均衡优化问题,提出一种自适应的云计算环境下虚拟机(VM)动态迁移软节能策略。该策略采用常用的硬件能耗感知技术——动态电压频率调节(DVFS)来实现分段优化的系统部件静态节能,又通过VM在线迁移技术实现云平台的动态自适应软件节能。在CloudSim云仿真平台下对比实现DVFS静态节能和自适应负载均衡的软节能策略,经PlanetLab云平台监测数据验证,结果表明:软硬结合的自适应能耗感知策略能够高效节能96%; DVFS+MAD_MMT节能策略(采用平均绝对偏差算法判定主机是否超载,基于最短迁移时间(MMT)原则选择VM移出) 相似文献
103.
赵梓涵 《辽宁石油化工大学学报》2018,38(5):19
近年来,在国家安全环保标准的要求下,油田污水问题通常以处理后回用锅炉方式解决。一方面解决了油田污水排放问题,另一方面节约了水资源。然而,污水回用锅炉过程由于各种原因造成污水处理系统及管线、锅炉、油泵等设施结垢严重。针对油田结垢问题,在了解结垢形成原因的基础上,首先介绍了结垢预测模型的发展状况,包括结合网络神经原理、层次分析、模糊分析等数值分析方法,利用MATLAB等工具拟合出的预测模型,在实际应用中,这些预测模型均达到了较高精度;其次介绍了油田结垢防治与控制方法的最新研究成果,包括加防垢剂以及防垢剂发展状况和对注入水本身进行改性解决其与地层水不配伍的问题,从而达到对油田结垢防治与控制的目的。 相似文献
104.
Hydrodynamic similarity in the fully developed zone of co-current upward gas-solid two-phase flow systems under different operating conditions was investigated by measuring the axial profiles of pressure gradient, radial profiles of solid concentration and particle velocity in two circulating fluidized bed (CFB) risers of 15.1 and 10.5 m high, with FCC and sand particles, respectively. The experimental data obtained from this work and in the literature show that when the scaling parameter, Gs/(ρpUg), is modified as , a detailed hydrodynamic similitude of the gas-solid flow in the fully developed zone of the risers under different operating conditions can be achieved. Furthermore, the experimental results from different gas-solid flow systems also show that as long as remains constant, there is the same solid concentration in the fully developed zone of different CFB risers with different particles. With the same , the local solid concentrations, the descending particle velocities, the cluster frequencies and the solid concentrations inside clusters in the fully developed zone of the risers all display the same axial and radial distribution, respectively. In other words, the empirical similarity parameter, , appears to have incorporated the effects of operating parameters (Gs and Ug), so that, the gas-solid flow in the fully developed zone of CFB risers under those different operating conditions but having the same shows similar micro- and macro-hydrodynamic characteristics. The study shows that the empirical similarity parameter, , is also independent of the upward gas-solid flow systems. 相似文献
105.
三旋是催化裂化装置能量回收系统的重要设备,其高效运行对烟机及整个催化装置都具有非常重要的意义。镇海某大型催化装置因三旋失效引起烟机入口烟气催化剂粒度超标,曾造成烟机两套转子动叶片磨损,装置不得已停工消缺。文章从卧式三旋的结构特点入手,结合三旋检修情况,分析其失效原因主要是由于三旋排尘泄气系统堵塞造成的窜流返混以及单管结垢,着重分析其形成机理,并制定了相应的对策。 相似文献
106.
W.N. Al Nasser F.H. Al-SalhiM.J. Hounslow A.D. Salman 《Chemical Engineering Research and Design》2011,89(5):500-511
The formation of mineral scale particularly calcium carbonate is a problem for industries ranging from oil and gas to desalination plants. Various techniques have been studied to prevent the formation of scale. The use of chemical inhibitors to prevent calcium carbonate agglomeration is widely studied. The present study attempts to show that the inline monitoring technique is a useful tool for laboratory experimental investigation of agglomeration phenomenon. This method is successful in providing the induction time of starting agglomeration. It was shown that the presence of inhibitor delays the agglomeration and affects the deposition of calcium carbonate.In addition the method is found useful in determining the minimum inhibitor concentration and also to screen various types of inhibitors for the selection. The influence of an inhibitor is studied on scaling solution of various calcium ion concentrations. Finally, the result of inline technique was validated by comparing with the conventional one called offline technique. The SEM images reveal that the mechanism of inhibition might be the surface adsorption or distortion of inhibitor molecules on the growing calcium carbonate crystals. 相似文献
107.
The Johnson‐Cook parameters for the zirconium material were determined based on the data obtained from the tensile testing of zirconium specimens at different strain‐rates and different temperatures. The velocity difference (VPL) between the particulated jet fragments was calculated for zirconium liners of different thicknesses using Johnson‐Cook constitutive equation. A breakup time formula for the zirconium shaped charge was proposed, which demonstrated better ductility performance than the copper shaped charge. 相似文献
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