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   1440833篇
  免费   25282篇
  国内免费   6991篇
电工技术   33934篇
综合类   6367篇
化学工业   266762篇
金属工艺   63111篇
机械仪表   39717篇
建筑科学   44380篇
矿业工程   11257篇
能源动力   50110篇
轻工业   102043篇
水利工程   14464篇
石油天然气   37272篇
武器工业   142篇
无线电   194132篇
一般工业技术   271414篇
冶金工业   139069篇
原子能技术   33694篇
自动化技术   165238篇
  2021年   15499篇
  2020年   11752篇
  2019年   14496篇
  2018年   14062篇
  2017年   13271篇
  2016年   20352篇
  2015年   17131篇
  2014年   28498篇
  2013年   87468篇
  2012年   33120篇
  2011年   44187篇
  2010年   40578篇
  2009年   49438篇
  2008年   41752篇
  2007年   38499篇
  2006年   42861篇
  2005年   37086篇
  2004年   39745篇
  2003年   39784篇
  2002年   39080篇
  2001年   35866篇
  2000年   34528篇
  1999年   33306篇
  1998年   37635篇
  1997年   34587篇
  1996年   32490篇
  1995年   28932篇
  1994年   27386篇
  1993年   27283篇
  1992年   25558篇
  1991年   22554篇
  1990年   23025篇
  1989年   22068篇
  1988年   20473篇
  1987年   18853篇
  1986年   18169篇
  1985年   21475篇
  1984年   21929篇
  1983年   19915篇
  1982年   19044篇
  1981年   19119篇
  1980年   17673篇
  1979年   18249篇
  1978年   17522篇
  1977年   16808篇
  1976年   17032篇
  1975年   15795篇
  1974年   15321篇
  1973年   15392篇
  1972年   12867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