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   48049篇
  免费   2350篇
  国内免费   66篇
电工技术   328篇
综合类   37篇
化学工业   11047篇
金属工艺   898篇
机械仪表   935篇
建筑科学   1516篇
矿业工程   88篇
能源动力   1503篇
轻工业   8923篇
水利工程   461篇
石油天然气   216篇
武器工业   3篇
无线电   2062篇
一般工业技术   7262篇
冶金工业   8448篇
原子能技术   259篇
自动化技术   6479篇
  2024年   90篇
  2023年   423篇
  2022年   929篇
  2021年   1441篇
  2020年   1028篇
  2019年   1176篇
  2018年   1666篇
  2017年   1668篇
  2016年   1824篇
  2015年   1415篇
  2014年   1794篇
  2013年   3536篇
  2012年   2785篇
  2011年   3095篇
  2010年   2385篇
  2009年   2249篇
  2008年   2107篇
  2007年   1894篇
  2006年   1444篇
  2005年   1249篇
  2004年   1144篇
  2003年   1045篇
  2002年   934篇
  2001年   674篇
  2000年   633篇
  1999年   709篇
  1998年   2938篇
  1997年   1906篇
  1996年   1281篇
  1995年   739篇
  1994年   602篇
  1993年   612篇
  1992年   214篇
  1991年   206篇
  1990年   160篇
  1989年   174篇
  1988年   181篇
  1987年   171篇
  1986年   126篇
  1985年   175篇
  1984年   134篇
  1983年   99篇
  1982年   101篇
  1981年   121篇
  1980年   121篇
  1978年   64篇
  1977年   201篇
  1976年   381篇
  1975年   60篇
  1973年   72篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Lobster krill (Munida genus) represents an under‐valued crustacean frequently caught on European fishing banks. In this work, its sensory, microbiological and biochemical qualities were evaluated during chilled storage. Additionally, the effects of a prestorage antimelanosic treatment consisting of soaking in sodium metabisulphite (SMB) solutions at two different concentrations (0.25% and 0.75%) were also studied. SMB prestorage treatment provided lobster specimens that still exhibited acceptable sensory quality after 10 days of storage, while control specimens were unacceptable at that time. SMB treatment also resulted in a significant (P < 0.05) inhibition of microbial growth, mainly of Enterobacteriaceae, psychrotrophes and proteolytic bacteria. Low lipid oxidation levels were observed for all batches; however, a significantly higher (P < 0.05) retention of polyunsaturated fatty acids was found in SMB‐treated lobster, especially in the 0.75% SMB batch. The results presented here open the way to the potential commercialisation of currently under‐utilised lobster krill as a chilled product.  相似文献   
2.
3.
4.
5.
6.
7.
ABSTRACT

In this paper, we review some algebraic control system. Precisely, linear and bilinear systems on Euclidean spaces and invariant and linear systems on Lie groups. The fourth classes of systems have a common issue: to any class, there exists an associated subgroup. From this object, we survey the controllability property. Especially, from those coming from our contribution to the theory.  相似文献   
8.
Context: The administration of pharmabiotics is a promising alternative to antimicrobial drugs for the treatment and/or prevention of female urogenital infections.

Objective: To design pharmabiotic formulations including bioactive ingredients of microbial origin combined with non-microbial substances and then to evaluate the stability of the combinations during freeze-drying and storage.

Materials and methods: Different formulations including Lactobacillus gasseri CRL 1263, Lactobacillus salivarius CRL 1328, salivaricin CRL 1328 (a bacteriocin) and non-microbial compounds (lactose, inulin and ascorbic acid) were assayed, and the ingredients were freeze-dried together or separately. The formulations were stored in gelatin capsules at 4?°C for 360?d.

Results: The viability of lactobacilli was affected to different extents depending on the strains and on the formulations assayed. L. salivarius and ascorbic acid were successfully combined only after the freeze-drying process. Salivaricin activity was not detected in formulations containing L. gasseri. However, when combined with ascorbic acid, lactose, inulin or L. salivarius, the bacteriocin maintained its activity for 360?d. The selected microorganisms proved to be compatible for their inclusion in multi-strain formulations together with lactose, inulin and ascorbic acid. Salivaricin could be included only in a L. salivarius CRL 1328 single-strain formulation together with non-microbial substances.

Conclusions: This study provides new insights into the design of urogenital pharmabiotics combining beneficial lactobacilli, salivaricin CRL 1328 and compounds with different functionalities.  相似文献   
9.
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