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   1547070篇
  免费   26430篇
  国内免费   7044篇
电工技术   35273篇
综合类   6414篇
化学工业   275914篇
金属工艺   66473篇
机械仪表   45213篇
建筑科学   47493篇
矿业工程   11770篇
能源动力   50830篇
轻工业   114204篇
水利工程   15513篇
石油天然气   38313篇
武器工业   144篇
无线电   200200篇
一般工业技术   294072篇
冶金工业   169402篇
原子能技术   34526篇
自动化技术   174790篇
  2021年   15936篇
  2020年   12112篇
  2019年   14959篇
  2018年   18860篇
  2017年   18548篇
  2016年   22979篇
  2015年   17865篇
  2014年   29175篇
  2013年   89264篇
  2012年   37297篇
  2011年   51884篇
  2010年   45796篇
  2009年   53998篇
  2008年   47723篇
  2007年   45468篇
  2006年   45448篇
  2005年   41346篇
  2004年   42677篇
  2003年   42355篇
  2002年   41025篇
  2001年   37476篇
  2000年   35879篇
  1999年   35188篇
  1998年   46257篇
  1997年   39915篇
  1996年   35736篇
  1995年   30962篇
  1994年   29164篇
  1993年   28976篇
  1992年   26273篇
  1991年   23356篇
  1990年   23725篇
  1989年   22813篇
  1988年   21304篇
  1987年   19573篇
  1986年   18949篇
  1985年   22220篇
  1984年   22425篇
  1983年   20338篇
  1982年   19346篇
  1981年   19473篇
  1980年   18055篇
  1979年   18554篇
  1978年   17784篇
  1977年   17665篇
  1976年   18745篇
  1975年   16072篇
  1974年   15565篇
  1973年   15629篇
  1972年   13080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.
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   
4.
5.
6.
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   
7.
Clean Technologies and Environmental Policy - Food production and consumption is one of the major causes of global environmental degradation. One way to address environmental impacts in the food...  相似文献   
8.
9.
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   
10.
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