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   557399篇
  免费   8337篇
  国内免费   1899篇
电工技术   9354篇
综合类   2659篇
化学工业   81560篇
金属工艺   24045篇
机械仪表   20346篇
建筑科学   14171篇
矿业工程   2951篇
能源动力   13327篇
轻工业   48090篇
水利工程   5988篇
石油天然气   7415篇
武器工业   13篇
无线电   65490篇
一般工业技术   109458篇
冶金工业   85610篇
原子能技术   9046篇
自动化技术   68112篇
  2021年   4111篇
  2020年   2714篇
  2019年   3359篇
  2018年   24000篇
  2017年   23713篇
  2016年   17660篇
  2015年   5045篇
  2014年   6999篇
  2013年   20434篇
  2012年   16092篇
  2011年   30452篇
  2010年   25721篇
  2009年   24356篇
  2008年   25404篇
  2007年   27657篇
  2006年   13390篇
  2005年   15990篇
  2004年   13952篇
  2003年   13475篇
  2002年   11437篇
  2001年   11015篇
  2000年   10362篇
  1999年   10815篇
  1998年   25849篇
  1997年   18201篇
  1996年   14045篇
  1995年   10536篇
  1994年   9366篇
  1993年   9083篇
  1992年   6767篇
  1991年   6481篇
  1990年   6043篇
  1989年   5955篇
  1988年   5728篇
  1987年   4746篇
  1986年   4573篇
  1985年   5603篇
  1984年   5062篇
  1983年   4673篇
  1982年   4246篇
  1981年   4386篇
  1980年   4012篇
  1979年   3978篇
  1978年   3835篇
  1977年   4369篇
  1976年   5684篇
  1975年   3280篇
  1974年   3112篇
  1973年   3191篇
  1972年   2488篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
41.
42.
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   
43.
This study aimed to evaluate the physicochemical characteristics and sensory attributes of beef burgers with the addition of pea fibre as a partial substitute of meat or fat. Three formulations were prepared: control (CON) – similar to the commercial formulation; fibre/less meat (FLM)—5% meat reduction and addition of 1% pea fibre; fibre/less fat (FLF)—7% fat reduction and addition of 1% pea fibre. Non-significant differences were obtained for pH, colour parameters (L* and b*), texture profile, cooking loss and size reduction among formulations. Moreover, sensory analysis with consumers of beef burgers did not indicate differences among the formulations for all the analysed attributes. Therefore, pea fibre is a promising partial replacer for meat and fat in beef burgers due to the preservation of technological parameters and sensory acceptance.  相似文献   
44.
Topics in Catalysis - In this work, a simple thermal-catalytic system was used to valorize peanut shells (Arachis hypogaea), the residual biomass from the peanut industry. To accomplish this...  相似文献   
45.
The role of the following factors in the selection of technological bases for manufacturing is considered: the accessibility of the machined surfaces; their parameters and dimensional relationships; their position relative to the forces acting; and the uniformity of the margin distribution.  相似文献   
46.
Polymer Bulletin - In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with...  相似文献   
47.
The price of cobalt has increased by some 450% in the past two years, mainly due to increasing demand for lithium–ion batteries. With an official 2017 production of 64 kt, the Democratic Republic of Congo produces more than half of the world’s cobalt. African Copperbelt operations have traditionally focused on copper production; however, it has now become imperative to also consider cobalt recovery from these ores. A plethora of processing routes is possible. Most hydrometallurgical flowsheets recover cobalt from the raffinate of the low-grade copper solvent-extraction circuit. Downstream purification processes include sequential precipitation with a variety of reagents, solvent extraction, and ion exchange. Product choices include hydroxide, carbonate, sulfate, and metal cathode. This study assesses technical and economic advantages and limitations of various approaches to the hydrometallurgical processing of cobalt in an African context.  相似文献   
48.
The bromodomain and extra terminal (BET) family of bromodomain-containing proteins (BCPs) have been the subject of extensive research over the past decade, resulting in a plethora of high-quality chemical probes for their tandem bromodomains. In turn, these chemical probes have helped reveal the profound biological role of the BET bromodomains and their role in disease, ultimately leading to a number of molecules in active clinical development. However, the BET subfamily represents just 8/61 of the known human bromodomains, and attention has now expanded to the biological role of the remaining 53 non-BET bromodomains. Rapid growth of this research area has been accompanied by a greater understanding of the requirements for an effective bromodomain chemical probe and has led to a number of new non-BET bromodomain chemical probes being developed. Advances since December 2015 are discussed, highlighting the strengths/caveats of each molecule, and the value they add toward validating the non-BET bromodomains as tractable therapeutic targets.  相似文献   
49.
50.
Multidimensional Systems and Signal Processing - The paper is devoted to the development of the octonion Fourier transform (OFT) theory initiated in 2011 in articles by Hahn and Snopek. It is also...  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