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   1609340篇
  免费   26408篇
  国内免费   7157篇
电工技术   35336篇
综合类   6498篇
化学工业   277575篇
金属工艺   66594篇
机械仪表   47172篇
建筑科学   48665篇
矿业工程   11912篇
能源动力   50510篇
轻工业   125539篇
水利工程   16544篇
石油天然气   38380篇
武器工业   149篇
无线电   200651篇
一般工业技术   303124篇
冶金工业   204672篇
原子能技术   34676篇
自动化技术   174908篇
  2021年   15652篇
  2020年   11980篇
  2019年   14792篇
  2018年   19071篇
  2017年   18884篇
  2016年   23104篇
  2015年   17648篇
  2014年   28812篇
  2013年   88185篇
  2012年   38707篇
  2011年   54180篇
  2010年   46282篇
  2009年   53890篇
  2008年   49604篇
  2007年   47627篇
  2006年   47217篇
  2005年   43141篇
  2004年   44234篇
  2003年   43820篇
  2002年   42370篇
  2001年   39416篇
  2000年   37440篇
  1999年   37102篇
  1998年   58061篇
  1997年   47195篇
  1996年   40389篇
  1995年   33783篇
  1994年   31202篇
  1993年   30990篇
  1992年   26895篇
  1991年   24186篇
  1990年   24466篇
  1989年   23507篇
  1988年   22108篇
  1987年   20239篇
  1986年   19652篇
  1985年   23009篇
  1984年   22784篇
  1983年   20801篇
  1982年   19590篇
  1981年   19684篇
  1980年   18335篇
  1979年   18826篇
  1978年   18014篇
  1977年   18322篇
  1976年   20005篇
  1975年   16237篇
  1974年   15692篇
  1973年   15826篇
  1972年   13264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