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81.
运用程序占空比概念及故障注入技术对星用微处理器动态和静态单粒子翻转率间的关系进行了研究,并将预估结果与国外在轨飞行监测数据进行了对比。结果表明,由程序占空比计算所得动态单粒子翻转率可对星用微处理器在轨单粒子翻转率进行合理预估;故障注入技术是灵活、方便的动态单粒子翻转率预估方法。 相似文献
82.
《Energy Policy》2016
The IEA/NEA recently issued their eighth edition of the Study on the “Projected Costs of Generating Electricity” – 2015 edition. The Study is mainly concerned with calculating the levelised cost of electricity (LCOE). The LCOE calculations are based on a levelised average life time cost approach using the discounted cash flow (DCF) method. The analysis was this year, and for the first time, performed using three discount rates (3%, 7%, and 10%). The LCOE can serve as a tool for calculating the cost of different generation technologies. However the Study's usefulness is affected by its narrow base of a limited set of countries that are not necessarily representative. It ignored the negative role of subsidies and did not provide a methodology for selective application of the discount rates and costing of carbon. The global power generation scene is changing. Generation growth in OECD countries has become very limited; simultaneously there is rapid growth of varying renewables (VRE) generation which needs special criteria for assessing its system cost. All this demands a rethinking of the application and usefulness of the LCOE in future generation planning. 相似文献
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采用直流热阴极PCVD方法间歇生长模式,在CH4-H2气氛常规制备微米晶金刚石膜的参数条件下,利用人工干预二次形核工艺,研究了间歇周期变化对制备纳米晶金刚石膜的影响.人工干预二次形核是指通过生长温度的周期性改变而诱发二次形核行为,从而实现金刚石膜的纳米晶生长.金刚石膜周期性生长过程分为沉积阶段和干预阶段,沉积阶段主要完成金刚石膜的生长,干预阶段将沉积温度降低到600℃,然后恢复到生长温度,即完成一个生长周期.间歇周期研究主要是考察在不同间歇时间里人工干预诱导二次形核的效果,间歇时间设定为1 min、5 min、10 min、15min、20 min,生长时间设为20 min,总的沉积时间为6 h.采用拉曼光谱仪、SEM和XRD对样品进行了分析,结果表明直流热阴极PCVD方法间歇生长模式,间歇周期的变化,对二次形核的发生有诱导作用,适当选择间歇周期,有利于二次形核基团的生成. 相似文献
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86.
LAS系统微晶玻璃的制备及析晶研究 总被引:2,自引:1,他引:1
采用烧结法和溶胶-凝胶法制备了LAS系统微晶玻璃,并研究了其析晶性能。结果表明,烧结法制备的样品中晶粒尺寸为100~150nm,分布均匀,主晶相为β-锂辉石相,另外含有少量的Moganite石英相,溶胶-凝胶法制备的样品中晶粒尺寸为10~60nm,分布均匀,样品中存在Al2O3和LiAlO2相,而SiO2没有结晶,形成玻璃体。核化温度为600℃、晶化温度为680℃时,微晶玻璃的结晶效果比较好。 相似文献
87.
This work presents a comparative assessment of engine oil performance on field test using urban transport vehicles powered by compressed natural gas engines using two different mineral oil formulations approved by engine manufacturer. The first one is considered as a baseline reference, and the second one is a higher quality formulation in terms of base stock refining and additive content. Higher quality oil has shown a significant enhanced lubricant performance, leading to reach the oil drain interval defined by engine manufacturer on these engines without penalties in maintenance costs. In order to assess oil performance, an oil analysis programme has been established for oil samples collected from vehicles operated under real service conditions in an urban transport fleet. Monitored parameters include oxidation, nitration, aminic anti‐oxidant additives depletion, anti‐wear additives depletion, total acid number, total basic number and remaining useful life number (as an estimation of anti‐oxidant additive depletion including aminic and zinc dialkyldithiophosphate). Results obtained in more than 90 samples from 15 different vehicles have shown higher degradation rates for low quality lubricant oil formulation. This deviation can be explained taking into account factors related with lower anti‐oxidant additives content and lower thermal stability that can be mainly related with the base stock quality. This lower oil performance can be finally converted into higher vehicle maintenance cost and lower engine reliability. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
88.
Rogelio álvarez Nikolai B. Gorev Inna F. Kodzhespirova Yuriy Kovalenko Eugenio Prokhorov Alfredo Ramos 《Canadian Metallurgical Quarterly》2011,137(3):393-397
This paper presents and discusses an extension of the pseudotransient continuation-based steady state solver for hydraulic networks proposed previously to the case of zero flow rates. The original solver, which reduces the solution of the governing nonlinear algebraic equations to the numerical integration of an initial-value problem, has problems in situations in which the head derivative of the flow rate tends to infinity, as is the case with zero flow rates. The extension is on the basis of the use of a model headloss-flow relationship that coincides with the true one at zero and has a finite head derivative at that point. This modified steady state solver is free from some convergence problems that occur in Newton-Raphson method-based solvers when analyzing a pipe network with control devices. The paper includes the results of the numerical analysis of test networks, which demonstrate the convergence of the modified steady state solver for cases in which existing steady state solvers have troubles. 相似文献
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90.
提出了一种适于无线网络的基于优先级竞争的协作媒质接入控制(PBC-CMAC)协议。该协议首先由源节点根据本地中继信息表选择2个最佳候选中继节点,以反映缩短传输时间程度的中继效率值区分优先级,并在CRTS分组中宣布。被选择的候选节点通过侦听源节点与目的节点交换的控制分组,可得到即时的相关速率信息,并结合自身优先级无冲突竞争成为最终的中继节点。该协议可以从所有可能的中继节点中快速、无冲突地选择出适于当前信道质量状态的最佳中继节点进行协作传输,提高了中继节点选择的成功率和协作效率,改善了网络接入性能。仿真结果表明,与IEEE 802.11 RTS/CTS和CoopMAC协议相比,PBC-CMAC协议有效提高了无线网络的多址性能。 相似文献