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   1525796篇
  免费   25684篇
  国内免费   6987篇
电工技术   34255篇
综合类   6485篇
化学工业   271712篇
金属工艺   64120篇
机械仪表   42750篇
建筑科学   47074篇
矿业工程   11376篇
能源动力   50231篇
轻工业   117929篇
水利工程   15499篇
石油天然气   37289篇
武器工业   136篇
无线电   196421篇
一般工业技术   288003篇
冶金工业   170483篇
原子能技术   33794篇
自动化技术   170910篇
  2021年   15601篇
  2020年   11852篇
  2019年   14635篇
  2018年   14856篇
  2017年   14053篇
  2016年   21069篇
  2015年   17376篇
  2014年   28787篇
  2013年   87902篇
  2012年   36182篇
  2011年   48473篇
  2010年   42220篇
  2009年   50385篇
  2008年   45375篇
  2007年   42607篇
  2006年   45632篇
  2005年   39888篇
  2004年   42440篇
  2003年   42295篇
  2002年   41344篇
  2001年   38386篇
  2000年   36651篇
  1999年   35626篇
  1998年   46952篇
  1997年   40594篇
  1996年   36356篇
  1995年   31509篇
  1994年   29563篇
  1993年   29110篇
  1992年   26541篇
  1991年   23629篇
  1990年   23875篇
  1989年   22954篇
  1988年   21451篇
  1987年   19726篇
  1986年   19190篇
  1985年   22573篇
  1984年   22692篇
  1983年   20573篇
  1982年   19428篇
  1981年   19494篇
  1980年   18097篇
  1979年   18744篇
  1978年   17924篇
  1977年   17988篇
  1976年   19540篇
  1975年   16110篇
  1974年   15646篇
  1973年   15720篇
  1972年   13209篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
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   
22.
23.
24.
25.
26.
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   
27.
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   
28.
29.
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   
30.
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