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   470994篇
  免费   7919篇
  国内免费   2607篇
电工技术   9018篇
技术理论   5篇
综合类   1345篇
化学工业   72862篇
金属工艺   17705篇
机械仪表   13775篇
建筑科学   12349篇
矿业工程   2152篇
能源动力   11819篇
轻工业   48460篇
水利工程   4634篇
石油天然气   7660篇
武器工业   248篇
无线电   55482篇
一般工业技术   87028篇
冶金工业   87469篇
原子能技术   8273篇
自动化技术   41236篇
  2021年   3905篇
  2020年   2804篇
  2019年   3455篇
  2018年   5452篇
  2017年   5440篇
  2016年   6005篇
  2015年   4599篇
  2014年   7492篇
  2013年   21447篇
  2012年   13078篇
  2011年   18059篇
  2010年   14190篇
  2009年   15621篇
  2008年   16741篇
  2007年   16882篇
  2006年   15206篇
  2005年   13512篇
  2004年   12542篇
  2003年   12110篇
  2002年   11670篇
  2001年   12064篇
  2000年   11096篇
  1999年   11541篇
  1998年   26729篇
  1997年   19177篇
  1996年   14622篇
  1995年   11092篇
  1994年   9964篇
  1993年   9704篇
  1992年   7237篇
  1991年   6876篇
  1990年   6813篇
  1989年   6557篇
  1988年   6285篇
  1987年   5221篇
  1986年   5145篇
  1985年   6094篇
  1984年   5703篇
  1983年   5251篇
  1982年   4703篇
  1981年   4961篇
  1980年   4529篇
  1979年   4608篇
  1978年   4362篇
  1977年   4758篇
  1976年   6114篇
  1975年   3804篇
  1974年   3592篇
  1973年   3673篇
  1972年   3006篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Qin  Yi  Tao  Xianping  Huang  Yu    Jian 《World Wide Web》2019,22(1):1-37
World Wide Web - Rule mechanism has been widely used in many areas, such as databases, artificial intelligent and pervasive computing. In a rule mechanism, rule activation decides which rules are...  相似文献   
2.
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   
3.
4.
5.
6.
7.
8.
Pinhão seed is an unconventional source of starch and the pines grow up in native forests of southern Latin America. In this study, pinhão starch was adjusted at 15, 20 and 25% moisture content and heated to 100, 110 and 120 °C for 1 h. A decrease in λ max (starch/iodine complex) was observed as a result of increase in temperature and moisture content of HMT. The ratio of crystalline to amorphous phase in pinhão starch was determined via Fourier transform infra red by taking 1045/1022 band ratio. A decrease in crystallinity occurred as a result of HMT. Polarised light microscopy indicated a loss of birefringence of starch granules under 120 °C at 25% moisture content. Granule size distribution was further confirmed via scanning electron microscopy which showed the HMT effects. These results increased the understanding on molecular and structural properties of HMT pinhão starch and broadened its food and nonfood industrial applications.  相似文献   
9.
The viability and β‐galactosidase activity of four Lactobacillus strains in milk drink containing gums during 28 days of refrigerated storage at 4 °C were assessed. The population of Lactobacillus rhamnosus GGB101 and Lactobacillus rhamnosus GGB103 were maintained, whereas the population of Lactobacillus reuteri DSM20016 and Lactobacillus reuteri SD2112 significantly decreased. The recommended level of 6 log CFU g?1 was exceeded for all tested trains throughout storage. The highest viable number of Lactobacillus rhamnosus GGB103 (8.76 ± 0.03 log CFU mL?1) was obtained in the product containing carrageenan–maltodextrin. The addition of guar–locust bean–carrageenan led to 20‐fold increase in the level of β‐galactosidase activity for L. rhamnosus GGB101 (1208 ± 2.12 Miller units mL?1) compared to the control (61 ± 2.83 Miller units mL?1). Our results suggested that gums could be added to milk to improve viability and enhance β‐galactosidase activity of Lactobacillus.  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