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   1544237篇
  免费   33919篇
  国内免费   7051篇
电工技术   34890篇
综合类   6418篇
化学工业   280843篇
金属工艺   64611篇
机械仪表   42953篇
建筑科学   47417篇
矿业工程   11389篇
能源动力   50744篇
轻工业   118045篇
水利工程   15540篇
石油天然气   37429篇
武器工业   131篇
无线电   200564篇
一般工业技术   289989篇
冶金工业   177891篇
原子能技术   33981篇
自动化技术   172372篇
  2021年   15672篇
  2020年   12826篇
  2019年   16794篇
  2018年   17201篇
  2017年   16642篇
  2016年   23514篇
  2015年   19719篇
  2014年   30993篇
  2013年   90992篇
  2012年   36995篇
  2011年   48895篇
  2010年   43647篇
  2009年   51984篇
  2008年   45827篇
  2007年   42670篇
  2006年   45677篇
  2005年   40162篇
  2004年   42446篇
  2003年   42153篇
  2002年   41264篇
  2001年   38148篇
  2000年   36537篇
  1999年   35699篇
  1998年   49246篇
  1997年   41748篇
  1996年   37119篇
  1995年   31775篇
  1994年   29658篇
  1993年   29501篇
  1992年   26308篇
  1991年   23599篇
  1990年   23814篇
  1989年   22910篇
  1988年   21440篇
  1987年   19703篇
  1986年   19027篇
  1985年   22390篇
  1984年   22412篇
  1983年   20389篇
  1982年   19352篇
  1981年   19485篇
  1980年   18135篇
  1979年   18626篇
  1978年   17896篇
  1977年   18032篇
  1976年   19780篇
  1975年   16127篇
  1974年   15612篇
  1973年   15708篇
  1972年   13169篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
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   
23.
24.
25.
26.
27.
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   
28.
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   
29.
30.
Programming and Computer Software - Image segmentation using a hierarchical sequence of piecewise constant approximations that minimally differ from the original image in terms of the total squared...  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