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   1479285篇
  免费   25826篇
  国内免费   6968篇
电工技术   34084篇
综合类   6391篇
化学工业   268812篇
金属工艺   63830篇
机械仪表   41131篇
建筑科学   45436篇
矿业工程   11287篇
能源动力   50164篇
轻工业   108313篇
水利工程   15019篇
石油天然气   37267篇
武器工业   131篇
无线电   195067篇
一般工业技术   277428篇
冶金工业   156504篇
原子能技术   33782篇
自动化技术   167433篇
  2021年   15548篇
  2020年   11824篇
  2019年   14564篇
  2018年   14479篇
  2017年   13622篇
  2016年   20672篇
  2015年   17231篇
  2014年   28598篇
  2013年   87680篇
  2012年   34257篇
  2011年   45709篇
  2010年   41253篇
  2009年   49827篇
  2008年   43157篇
  2007年   40028篇
  2006年   43833篇
  2005年   38218篇
  2004年   40727篇
  2003年   40675篇
  2002年   39961篇
  2001年   36742篇
  2000年   35205篇
  1999年   34286篇
  1998年   42506篇
  1997年   37674篇
  1996年   34444篇
  1995年   30203篇
  1994年   28420篇
  1993年   28281篇
  1992年   25969篇
  1991年   23140篇
  1990年   23393篇
  1989年   22510篇
  1988年   21015篇
  1987年   19312篇
  1986年   18647篇
  1985年   22005篇
  1984年   22220篇
  1983年   20201篇
  1982年   19237篇
  1981年   19320篇
  1980年   17923篇
  1979年   18472篇
  1978年   17746篇
  1977年   17533篇
  1976年   18761篇
  1975年   16008篇
  1974年   15516篇
  1973年   15574篇
  1972年   13051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