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   1613636篇
  免费   26673篇
  国内免费   7097篇
电工技术   34856篇
综合类   6531篇
化学工业   276214篇
金属工艺   65891篇
机械仪表   45648篇
建筑科学   48465篇
矿业工程   11624篇
能源动力   50514篇
轻工业   125512篇
水利工程   16456篇
石油天然气   37873篇
武器工业   153篇
无线电   199508篇
一般工业技术   299537篇
冶金工业   220402篇
原子能技术   34330篇
自动化技术   173892篇
  2021年   15704篇
  2020年   12076篇
  2019年   14811篇
  2018年   17693篇
  2017年   16973篇
  2016年   22415篇
  2015年   17706篇
  2014年   28949篇
  2013年   88442篇
  2012年   38209篇
  2011年   52304篇
  2010年   44741篇
  2009年   52350篇
  2008年   48442篇
  2007年   45950篇
  2006年   46952篇
  2005年   42048篇
  2004年   43800篇
  2003年   43456篇
  2002年   42236篇
  2001年   39652篇
  2000年   37632篇
  1999年   37794篇
  1998年   62815篇
  1997年   49942篇
  1996年   42434篇
  1995年   34878篇
  1994年   32124篇
  1993年   32045篇
  1992年   27167篇
  1991年   24515篇
  1990年   24629篇
  1989年   23755篇
  1988年   22315篇
  1987年   20476篇
  1986年   19840篇
  1985年   23137篇
  1984年   22814篇
  1983年   20755篇
  1982年   19673篇
  1981年   19859篇
  1980年   18493篇
  1979年   18842篇
  1978年   18142篇
  1977年   18887篇
  1976年   21666篇
  1975年   16285篇
  1974年   15723篇
  1973年   15827篇
  1972年   13283篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
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   
33.
34.
Metallurgical and Materials Transactions A - The influence of the chemical composition on the crystallization process, amorphous phase formation, and the anticorrosion properties of Al-Zr-Ni-Fe-Y...  相似文献   
35.
Powder Metallurgy and Metal Ceramics - The infiltration of aluminum melts into porous metal skeletons produced by powder metallurgy methods, including 3D printing, under a pressure gradient was...  相似文献   
36.
37.
38.
39.
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   
40.
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   
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