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991.
992.
Building cooling heating power (BCHP) systems as a kind of distributed energy resource have shown a great potential in improving energy efficiency and meeting multiple energy demands in buildings. In this paper, we present a BCHP system driven by solar energy with flat‐plate solar collectors. A modified system efficiency is introduced to evaluate the whole day performance of the system more accurately. Based on the mathematical models and simulation platform established, we have investigated the influences of some key thermodynamic parameters, namely condensation temperature, turbine inlet temperature and turbine inlet pressure on the system performance. In order to find the optimum combination of these parameters that leads to the best performance, we have performed parametric optimization by means of the genetic algorithm. Results indicate that the best performance and the highest efficiency of the system are achieved when the working fluid reaches its saturated state and the corresponding efficiencies of the system operating in the combined heating power mode, the combined cooling power mode and the power production mode turn out to be 19.10%, 27.24% and 10.47%, respectively. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
993.
The major objective of the paper is to address the main weakness of the reverse Monte-Carlo method applied to jet fire simulation; its slow convergence rate. This is done by replacing the use of a pseudo-random number generator for calculating ray orientations with a ray direction specification based on Sobol sequences. Sobol sequences produce sequences of points on the unit hemisphere that are not independent of each other in that new points in the sequence avoid previous points generated. This has the property that a more uniform pattern of rays on the unit hemisphere is produced, giving a ray convergence rate for the incident heat flux that is asymptotically equivalent to O(NRay−1). The use of Sobol sequences to accelerate convergence of the Monte-Carlo method has been applied in mathematical physics and financial modelling but the results presented here are the first study of quasi-Monte-Carlo methods applied to the incident heat flux integral. The use of Sobol sequences to generate ray directions means that the Central Limit Theorem no longer holds. In its place, it has been demonstrated that it is possible to construct a Gaussian variable from the incident intensity distributions calculated using Sobol sequences. This means it is possible to calculate confidence limits for a prediction of incident heat flux and the confidence limits contract with ray number at a rate of O(NRay−1 ln(NRay)). 相似文献
994.
针对太阳能聚光器薄膜在制备过程中牢固度不理想这一问题,确定在薄膜的生长过程中影响薄膜牢固度的各个因素,对这些因素作了具体的分析,并在实验的基础上,给出了提高薄膜牢固度的具体措施。 相似文献
995.
微波输能技术(MPT)是实现远距离能量无线传输的主要方式之一,也是空间太阳能电站系统的核心技术之一.本文主要介绍了微波输能技术的国内外研究现状,并对微波输能技术的系统组成与关键技术做了分析,其中主要针对微波发射子系统与微波接收子系统两大模块进行了详细的讨论.最后,对微波输能系统技术所存在的问题以及未来发展的趋势进行了概括. 相似文献
996.
UV固化材料进展 总被引:17,自引:0,他引:17
杨永源 《精细与专用化学品》2001,9(7):9-12
由于UV固化技术固有的特点使其在近几年各个领域都获得了高速的发展,但所占市场份额仍然很小。经过学术界和各大公司的努力,目前已经在UV固化材料方面取得了可喜的成绩。稀释单体、预聚体在数量和质量上都有大幅度增加,发展方向是降低刺激性、低毒和赋予特殊功能:在双光子引发自由基聚合、阳离子光固化、杂混光固化、光产碱催化聚合、无光引发剂光固化、水基固化方面取得了一定的进展;UV粉末涂料克服了传统粉末涂料的缺点脱颖而出,成为近年来研究开发的热点;UV固化纳米材料更是集纳米技术、纳米材料、UV固化技术于一体,预计将会开发出具有特殊功能的新材料;UV固化技术在电子、信息领域也具有很好的发展前景。 相似文献
997.
Mengu Cho 《Electrical Engineering in Japan》2009,166(4):1-8
Secondary arc on solar arrays in space in defined as an arc discharge short‐circuiting adjacent solar cells. As the operational voltage of spacecraft increases to 100 V, there is more risk of secondary arc that can destroy solar array circuits. Secondary arc is categorized as a vacuum arc, although its current is very low, even less than 1 A. One‐dimensional modeling is carried out to derive sets of parameters that satisfy the governing equations. Genetic algorithm is used to find the optimal set of solutions. Even at a current less than 1 A, the solutions exist though the arc voltage is higher than the experimental values by several tens of volts. ©2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 1– 8, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20571 相似文献
998.
Mechanical blends of thermoplastic medium density polyethylene (MDPE) and elastomeric ethylene propylene diene monomer (EPDM) have been prepared with a fixed composition of 60/40 wt%. They have been used either in their gum form or loaded with two different reinforcing fillers, high abrasion furnace (HAF) carbon black or precipitated SiO2 (Hi Sil) of concentration 25–100 phr (parts per hundred parts of resin) with respect to the blend. Curing was achieved by gamma irradiation. Yielding properties (yield stress, yield strain and cold drawing) have been followed as a function of irradiation dose for different blend compositions. Yield stress values increased with irradiation dose and with the content of the reinforcing filler, but yield strain and cold drawing values decreased with irradiation dose and also with the filler content. The data obtained reveal that Hi Sil is more effective as a reinforcing filler, and the prepared blends are suitable for load‐bearing applications. © 2001 Society of Chemical Industry 相似文献
999.
Franco Cataldo 《Polymer International》2001,50(7):828-834
Radiation damage to fillers such as carbon black, graphite and silica induced by high doses of γ‐radiation or neutrons dramatically increases their ability to adsorb rubber irreversibly. In fact, the ‘bound rubber’, ie the amount of non‐extractable rubber which remains irreversibly linked to the filler matrix, increases dramatically in radiation‐treated fillers. The increased adsorption power of radiation‐damaged fillers has been attributed to the formation of a higher concentration of surface defects in the form of trapped free radicals, fullerene‐like structures and other kinds of defects. The mechanical properties of rubber compounds filled with radiation‐treated carbon blacks show a significant increase in their reinforcing effects, in line with the increased ability to form ‘bound rubber’. © 2001 Society of Chemical Industry 相似文献
1000.
利用分光光度计对建筑材料表面,对紫外到近红外线范围(240~15000nm)内的正分光透射比、正分光反射比进行测定.另外,还利用积分球对紫外到红外线范围(240~2200nm)内的漫射比谱进行测定,同时将测定结果与正分光透射比、反射比进行比较,并计算出太阳吸收比及热放射比. 相似文献