全文获取类型
收费全文 | 4506篇 |
免费 | 710篇 |
国内免费 | 530篇 |
专业分类
电工技术 | 406篇 |
综合类 | 503篇 |
化学工业 | 496篇 |
金属工艺 | 79篇 |
机械仪表 | 191篇 |
建筑科学 | 140篇 |
矿业工程 | 58篇 |
能源动力 | 92篇 |
轻工业 | 277篇 |
水利工程 | 64篇 |
石油天然气 | 136篇 |
武器工业 | 71篇 |
无线电 | 540篇 |
一般工业技术 | 354篇 |
冶金工业 | 219篇 |
原子能技术 | 25篇 |
自动化技术 | 2095篇 |
出版年
2024年 | 30篇 |
2023年 | 97篇 |
2022年 | 129篇 |
2021年 | 142篇 |
2020年 | 200篇 |
2019年 | 180篇 |
2018年 | 133篇 |
2017年 | 196篇 |
2016年 | 197篇 |
2015年 | 193篇 |
2014年 | 263篇 |
2013年 | 395篇 |
2012年 | 331篇 |
2011年 | 304篇 |
2010年 | 251篇 |
2009年 | 252篇 |
2008年 | 287篇 |
2007年 | 306篇 |
2006年 | 270篇 |
2005年 | 246篇 |
2004年 | 228篇 |
2003年 | 181篇 |
2002年 | 157篇 |
2001年 | 118篇 |
2000年 | 111篇 |
1999年 | 87篇 |
1998年 | 72篇 |
1997年 | 59篇 |
1996年 | 41篇 |
1995年 | 45篇 |
1994年 | 31篇 |
1993年 | 30篇 |
1992年 | 26篇 |
1991年 | 15篇 |
1990年 | 23篇 |
1989年 | 13篇 |
1988年 | 16篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1964年 | 3篇 |
1963年 | 4篇 |
1957年 | 3篇 |
排序方式: 共有5746条查询结果,搜索用时 0 毫秒
1.
用于单芯片系统的改进型WXGA LCoS成像器 总被引:1,自引:1,他引:0
WillemA.Sloof MmthewS.Brennesholtz 《现代显示》2004,(3):36-39
本文讨论用于单芯片时序混色的菲利浦DD-720硅基液晶(LCoS)片。这种芯片主要用于HDTV背投影机和多媒体系统。与菲利浦以前的单片LCoS设计相比,由于该芯片具有电接口接点较少、封装简单和温度传感器内置等许多特点,使其应用于投影系统时成本降低。 相似文献
2.
Steven Y. Susswein Thomas C. Henderson Joseph L. Zachary Chuck Hansen Paul Hinker Gary C. Marsden 《International journal of parallel programming》1991,20(6):453-473
Filtering algorithms are well accepted as a means of speeding up the solution of the consistent labeling problem (CLP). Despite the fact that path consistency does a better job of filtering than arc consistency, AC is still the preferred technique because it has a much lower time complexity. We are implementing parallel path consistency algorithms on multiprocessors and comparing their performance to the best sequential and parallel arc consistency algorithms.(1,2) (See also work by Kerethoet al.
(3) and Kasif(4)) Preliminary work has shown linear performance increases for parallelized path consistency and also shown that in many cases performance is significantly better than the theoretical worst case. These two results lead us to believe that parallel path consistency may be a superior filtering technique. Finally, we have implemented path consistency as an outer product computation and have obtained good results (e.g., linear speedup on a 64K-node Connection Machine 2). 相似文献
3.
Ana MRB Xavier Ana Paula M Tavares Margarida SM Agapito Dmitry V Evtuguin 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(12):1602-1608
BACKGROUND: A sequential batch reactor (SBR) was used for eucalypt kraft pulp effluent treatment with Trametes versicolor. A 23 full factorial design and response surface methodology were applied to optimise the batch fermentation conditions. Effluent concentration, culture medium and inoculum age were the factors selected for this study in order to optimise the reduction of chemical oxygen demand (COD). RESULTS: The presence of Trametes Defined Medium (TDM) in the fermentation was required to obtain a significant COD reduction. Experiments in the batch reactor confirmed, in general, the predicted results of optimisation developed from Erlenmeyer batch assays. The T. versicolor culture remained active during 42 days of study in the SBR, providing approximately 80% of COD reduction. CONCLUSION: Trametes versicolor may be considered as very promising for the biological treatment of effluents from kraft pulp mills in an SBR system instead of the activated sludge mixed cultures traditionally used. Copyright © 2008 Society of Chemical Industry 相似文献
4.
结合兰州市的水泥标准稠度用水量方法测定 (代用法 )的实例 ,分析代用法测定标准稠度用水量的缺点 ,并对此方法提出了一些改进措施 相似文献
5.
We propose a general modeling framework to evaluate the performance of cache consistency algorithms. In addition to the usual hit rate, we introduce the hit* rate as a consistency measure, which captures the fraction of non-stale downloads from the cache. We apply these ideas to the analysis of the fixed TTL consistency algorithm in the presence of network delays. The hit and hit* rates are evaluated when requests and updates are modeled by renewal processes. Classical results on the renewal function lead to various bounds. 相似文献
6.
Abstract. The estimation of the spectral density function of a stationary Gaussian process at the input of an instantaneous nonlinearity is considered when the nonlinearity is known and a finite set of observations of the output process is given. A class of spectral estimates is considered and their quadratic-mean consistency is established; precise asymptotic expressions for their bias and covariance are derived and their asymptotic normality is obtained. 相似文献
7.
保序回归的大样本性质 总被引:1,自引:0,他引:1
邢务强 《西安邮电学院学报》2004,9(4):110-112
利用保序回归与极大似然估计之间的关系,从极大似然估计解的大样本性质出发,得到了保序回归解的两个大样本性质。 相似文献
8.
Scale and sludge from Bulalo geothermal field, Philippines, have been characterized by whole rock analysis, radioactivity counting, size analysis, light microscopy, scanning electron microscopy, and X-ray diffraction. Their leachability was assessed by regulatory leaching procedures and by sequential extraction. Both scale and sludge consisted mostly of oxides of Si, Al, and Fe with no radionuclides detected. The scale had 10% S content. Sulfides and silicates were important phases in both samples having size ranges from submicron to 2 mm. Geothermal soils at Bulalo have higher than normal soil levels of As, S, Cu, Cr, Zn, and Pb but regulatory leaching tests indicated that these elements are not released. However, the sequential extraction showed that As, Cu, and Zn were leachable under extreme conditions. 相似文献
9.
10.
Repeated reference creates strong expectations in addressees that a speaker will continue to use the same expression for the same object. The authors investigate the root reason for these expectations by comparing a cooperativeness-based account (Grice, 1975) with a simpler consistency-based account. In two eye-tracking experiments, the authors investigated the expectations underlying the effect of precedents on comprehension. The authors show that listeners expect speakers to be consistent in their use of expressions even when these expectations cannot be motivated by the assumption of cooperativeness. The authors conclude that though this phenomenon seems to be motivated by cooperativeness, listeners' expectation that speakers be consistent in their use of expressions is governed by a general expectation of consistency. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献