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   1514574篇
  免费   26780篇
  国内免费   7152篇
电工技术   34699篇
综合类   6410篇
化学工业   273043篇
金属工艺   65048篇
机械仪表   43122篇
建筑科学   46236篇
矿业工程   11596篇
能源动力   50438篇
轻工业   113517篇
水利工程   15325篇
石油天然气   37995篇
武器工业   143篇
无线电   197552篇
一般工业技术   285202篇
冶金工业   163797篇
原子能技术   34158篇
自动化技术   170225篇
  2021年   15871篇
  2020年   12147篇
  2019年   14928篇
  2018年   17010篇
  2017年   16445篇
  2016年   22075篇
  2015年   17695篇
  2014年   29002篇
  2013年   88419篇
  2012年   36011篇
  2011年   48856篇
  2010年   43499篇
  2009年   51959篇
  2008年   45405篇
  2007年   42820篇
  2006年   44602篇
  2005年   39826篇
  2004年   41620篇
  2003年   41390篇
  2002年   40396篇
  2001年   36912篇
  2000年   35466篇
  1999年   34635篇
  1998年   45285篇
  1997年   39298篇
  1996年   35355篇
  1995年   30668篇
  1994年   28685篇
  1993年   28653篇
  1992年   26027篇
  1991年   23152篇
  1990年   23507篇
  1989年   22584篇
  1988年   21086篇
  1987年   19435篇
  1986年   18710篇
  1985年   22056篇
  1984年   22272篇
  1983年   20223篇
  1982年   19195篇
  1981年   19349篇
  1980年   17974篇
  1979年   18483篇
  1978年   17732篇
  1977年   17537篇
  1976年   18373篇
  1975年   16026篇
  1974年   15530篇
  1973年   15609篇
  1972年   13098篇
排序方式: 共有10000条查询结果,搜索用时 0 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.
In this study, amaranth flour was used as an ingredient to prepare gluten-free cookies. The production process and attributes of amaranth cookies were characterised, and the potential use of amaranth flour as a functional ingredient was analysed. Cookies exhibited a non-uniform reddish brown colour and a cookie factor ratio of 4.5 ± 0.6. Storage studies indicated that after 3 weeks at room temperature cookies presented slight variations in the texture. Simulated gastrointestinal digestion of this product was able to release peptides capable of exerting potential antithrombotic and antihypertensive activities, IC50 values of 0.22 ± 0.04 and 0.23 ± 0.03 mg mL−1 protein, respectively. This work demonstrates for the first time that food made with amaranth flour exerts potential antithrombotic and antihypertensive activity. In conclusion, these amaranth cookies could be an alternative way of incorporating potentially health beneficial products for people who choose a conscious diet, including coeliac or vegan consumers.  相似文献   
6.
7.
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   
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