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   276210篇
  免费   5170篇
  国内免费   1155篇
电工技术   4641篇
综合类   426篇
化学工业   41625篇
金属工艺   8709篇
机械仪表   7778篇
建筑科学   7640篇
矿业工程   628篇
能源动力   8067篇
轻工业   32038篇
水利工程   2328篇
石油天然气   1985篇
武器工业   11篇
无线电   35149篇
一般工业技术   49572篇
冶金工业   51793篇
原子能技术   3537篇
自动化技术   26608篇
  2022年   1486篇
  2021年   2518篇
  2020年   1846篇
  2019年   2237篇
  2018年   3179篇
  2017年   3267篇
  2016年   3522篇
  2015年   2685篇
  2014年   4414篇
  2013年   13220篇
  2012年   7834篇
  2011年   11054篇
  2010年   8475篇
  2009年   9444篇
  2008年   9842篇
  2007年   9753篇
  2006年   8912篇
  2005年   8203篇
  2004年   7976篇
  2003年   7812篇
  2002年   7296篇
  2001年   7610篇
  2000年   6773篇
  1999年   7232篇
  1998年   18044篇
  1997年   12466篇
  1996年   9347篇
  1995年   7027篇
  1994年   6117篇
  1993年   6015篇
  1992年   4165篇
  1991年   4006篇
  1990年   3739篇
  1989年   3527篇
  1988年   3447篇
  1987年   2722篇
  1986年   2627篇
  1985年   3307篇
  1984年   2901篇
  1983年   2634篇
  1982年   2452篇
  1981年   2490篇
  1980年   2298篇
  1979年   2119篇
  1978年   1943篇
  1977年   2296篇
  1976年   2930篇
  1975年   1654篇
  1974年   1521篇
  1973年   1596篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
1.
Alcohol-free beer with isotonic properties is getting more popular and its production can be carried out by different production strategies; however, interrupted fermentation is still a challenge. Therefore, the objective of this study was to develop a low-alcohol isotonic beer (<0.5% v/v) by interrupted fermentation. Moreover, the major objective is to compare the developed product to commercial beverages (sports drinks, ‘Pilsen' regular beer, alcohol-free beers and low-alcohol isotonic beer). The beverages were evaluated based on pH, alcohol content (% v/v), total titratable acidity (mEq L−1), osmolality (mOsmol kg−1), bitterness International Bitterness Units, colour European Brewery Convention, total phenolic compounds (mg L−1 gallic acid), reducing and total sugars (%) and Na and K contents (mg L−1). The developed low-alcohol isotonic beer presented characteristics similar to sports drinks, with the advantage of being richer in phenolic compounds and suitable osmolality. Despite salts were added in its formulation, the grades attributed to all beers employed in the sensory evaluation, as well as the purchase intention did not present significant differences.  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.
Here we report some recent biophysical issues on the preparation of solute-filled lipid vesicles and their relevance to the construction of “synthetic cells.” First, we introduce the “semi-synthetic minimal cells” as the liposome-based cell-like systems, which contain a minimal number of biomolecules required to display simple and complex biological functions. Next, we focus on recent aspects related to the construction of synthetic cells. Emphasis is given to the interplay between the methods of synthetic cell preparation and the physics of solute encapsulation. We briefly introduce the notion of structural and compositional “diversity” in synthetic cell populations.  相似文献   
7.
8.
9.
10.
A contact layer element for large deformations   总被引:1,自引:0,他引:1  
  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