首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1589035篇
  免费   26732篇
  国内免费   7073篇
电工技术   34768篇
综合类   6552篇
化学工业   275897篇
金属工艺   65426篇
机械仪表   45102篇
建筑科学   48411篇
矿业工程   11581篇
能源动力   50466篇
轻工业   125000篇
水利工程   16200篇
石油天然气   37743篇
武器工业   142篇
无线电   198901篇
一般工业技术   298545篇
冶金工业   199650篇
原子能技术   34172篇
自动化技术   174284篇
  2021年   15769篇
  2020年   12030篇
  2019年   14803篇
  2018年   16623篇
  2017年   15951篇
  2016年   22114篇
  2015年   17713篇
  2014年   29052篇
  2013年   88586篇
  2012年   37893篇
  2011年   51590篇
  2010年   44153篇
  2009年   51968篇
  2008年   47808篇
  2007年   45437篇
  2006年   46898篇
  2005年   41766篇
  2004年   43732篇
  2003年   43448篇
  2002年   42328篇
  2001年   39437篇
  2000年   37517篇
  1999年   36989篇
  1998年   55419篇
  1997年   45963篇
  1996年   39879篇
  1995年   33643篇
  1994年   31189篇
  1993年   30805篇
  1992年   27070篇
  1991年   24303篇
  1990年   24494篇
  1989年   23642篇
  1988年   22169篇
  1987年   20290篇
  1986年   19798篇
  1985年   23147篇
  1984年   23030篇
  1983年   20904篇
  1982年   19676篇
  1981年   19800篇
  1980年   18442篇
  1979年   18965篇
  1978年   18179篇
  1977年   18791篇
  1976年   21198篇
  1975年   16331篇
  1974年   15779篇
  1973年   15886篇
  1972年   13380篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
This paper presents part of the work ComEd and Quanta Technology have performed to quantify the locational and temporal value of DER to avoid distribution grid upgrade investments. It focuses on the formulation of a robust and efficient algorithm for DER optimal dispatch on a distribution feeder to mitigate the violation of current and voltage limits using the allocated cost of capacity and locational marginal value of real and reactive DER injection/withdrawal.  相似文献   
2.
3.
Russian Engineering Research - Models based on regression analysis for predicting the operational efficiency of high-pressure roller crushers are considered. A systematized and structured...  相似文献   
4.
Journal of Machinery Manufacture and Reliability - A device based on smart alloys has been designed for use in machine building items, in particular, in nuclear engineering, for preventing...  相似文献   
5.
Journal of Machinery Manufacture and Reliability - The problem of calculating the reliability and fatigue life of machine parts by the fatigue failure under random changes in the actual and limit...  相似文献   
6.
In this paper, we present a novel memory access reduction scheme (MARS) for two-dimension fast cosine transform (2-D FCT). It targets programmable DSPs with high memory-access latency. It reduces the number of memory accesses by: 1) reducing the number of weighting factors and 2) combining butterflies in vector-radix 2-D FCT pruning diagram from two stages to one stage with an efficient structure. Hardware platform based on general purpose processor is used to verify the effectiveness of the proposed method for vector-radix 2-D FCT pruning implementation. Experimental results validate the benefits of the proposed method with reduced memory access, less clock cycle and fewer memory space compared with the conventional implementation.  相似文献   
7.
8.
9.
One specific class of non-linear evolution equations, known as the Tzitzéica-type equations, has received great attention from a group of researchers involved in non-linear science. In this article, new exact solutions of the Tzitzéica-type equations arising in non-linear optics, including the Tzitzéica, Dodd–Bullough–Mikhailov and Tzitzéica–Dodd–Bullough equations, are obtained using the expa function method. The integration technique actually suggests a useful and reliable method to extract new exact solutions of a wide range of non-linear evolution equations.  相似文献   
10.
ABSTRACT

Bacteriocin is a proteinaceous biomolecule produced by bacteria (both Gram-positive and Gram-negative) that exhibits antimicrobial activity against closely related species, and food-borne pathogens. It has recently gained importance and attracted the attention of several researchers looking to produce it from various substrates and bacterial strains. This ushers in a new era of food preservation where the use of bacteriocin in food products will be an alternative to chemical preservatives, and heat treatment which are understood to cause unwanted side effects, and reduce sensory and nutritional quality. However, this new market depends on the success of novel downstream separation schemes from various types of crude feedstocks which are both effective and economic. This review focuses on the downstream separation of bacteriocin from various sources using both conventional and novel techniques. Finally, recommendations for future interesting areas of research that need to be pursued are highlighted.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号