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   1720679篇
  免费   30835篇
  国内免费   9108篇
电工技术   38625篇
技术理论   5篇
综合类   9629篇
化学工业   290054篇
金属工艺   70324篇
机械仪表   51927篇
建筑科学   53594篇
矿业工程   13977篇
能源动力   52237篇
轻工业   135190篇
水利工程   17906篇
石油天然气   42306篇
武器工业   560篇
无线电   208080篇
一般工业技术   316086篇
冶金工业   239980篇
原子能技术   35475篇
自动化技术   184667篇
  2021年   18289篇
  2020年   13950篇
  2019年   16508篇
  2018年   21887篇
  2017年   21780篇
  2016年   25205篇
  2015年   19872篇
  2014年   31586篇
  2013年   91570篇
  2012年   43282篇
  2011年   60294篇
  2010年   50686篇
  2009年   57673篇
  2008年   54106篇
  2007年   52308篇
  2006年   51047篇
  2005年   46837篇
  2004年   46965篇
  2003年   46286篇
  2002年   44538篇
  2001年   41319篇
  2000年   39479篇
  1999年   39999篇
  1998年   68761篇
  1997年   54064篇
  1996年   45250篇
  1995年   36899篇
  1994年   33690篇
  1993年   33378篇
  1992年   27823篇
  1991年   25087篇
  1990年   25262篇
  1989年   24362篇
  1988年   22889篇
  1987年   20955篇
  1986年   20324篇
  1985年   23596篇
  1984年   23054篇
  1983年   21022篇
  1982年   19832篇
  1981年   20016篇
  1980年   18641篇
  1979年   18950篇
  1978年   18231篇
  1977年   19111篇
  1976年   21856篇
  1975年   16345篇
  1974年   15749篇
  1973年   15914篇
  1972年   13370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.
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.
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   
9.
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