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   1636007篇
  免费   26158篇
  国内免费   7067篇
电工技术   35467篇
综合类   6552篇
化学工业   279269篇
金属工艺   67504篇
机械仪表   48205篇
建筑科学   49102篇
矿业工程   11903篇
能源动力   50573篇
轻工业   129058篇
水利工程   16624篇
石油天然气   38383篇
武器工业   146篇
无线电   201564篇
一般工业技术   309359篇
冶金工业   213435篇
原子能技术   34607篇
自动化技术   177481篇
  2021年   15755篇
  2019年   14814篇
  2018年   19368篇
  2017年   19069篇
  2016年   23314篇
  2015年   17849篇
  2014年   29076篇
  2013年   88750篇
  2012年   39479篇
  2011年   55181篇
  2010年   46706篇
  2009年   54464篇
  2008年   50431篇
  2007年   48745篇
  2006年   47517篇
  2005年   43526篇
  2004年   44935篇
  2003年   44338篇
  2002年   42905篇
  2001年   40017篇
  2000年   38000篇
  1999年   37748篇
  1998年   59449篇
  1997年   48220篇
  1996年   41449篇
  1995年   34496篇
  1994年   32029篇
  1993年   31504篇
  1992年   27371篇
  1991年   24680篇
  1990年   24853篇
  1989年   24004篇
  1988年   22523篇
  1987年   20634篇
  1986年   20214篇
  1985年   23591篇
  1984年   23193篇
  1983年   21111篇
  1982年   19782篇
  1981年   19918篇
  1980年   18571篇
  1979年   19106篇
  1978年   18234篇
  1977年   19083篇
  1976年   21833篇
  1975年   16393篇
  1974年   15908篇
  1973年   15996篇
  1972年   13480篇
  1971年   12047篇
排序方式: 共有10000条查询结果,搜索用时 15 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