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   1059篇
  免费   1篇
化学工业   4篇
金属工艺   1篇
能源动力   2篇
轻工业   4篇
水利工程   2篇
石油天然气   1篇
一般工业技术   3篇
冶金工业   1036篇
自动化技术   7篇
  2021年   1篇
  2019年   1篇
  2018年   2篇
  2015年   1篇
  2013年   1篇
  2012年   1篇
  2011年   1篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2003年   3篇
  1999年   34篇
  1998年   327篇
  1997年   162篇
  1996年   125篇
  1995年   56篇
  1994年   69篇
  1993年   71篇
  1992年   5篇
  1991年   12篇
  1990年   12篇
  1989年   8篇
  1988年   10篇
  1987年   8篇
  1986年   8篇
  1985年   7篇
  1983年   1篇
  1982年   2篇
  1981年   9篇
  1980年   13篇
  1979年   3篇
  1978年   2篇
  1977年   33篇
  1976年   64篇
  1975年   3篇
  1954年   2篇
排序方式: 共有1060条查询结果,搜索用时 0 毫秒
911.
912.
913.
In 181 patients six reconstructive procedures were performed after total gastrectomy: Roux-en-Y (95), Henley (42), omega (21), Tomoda (16, Rosanov (4) and neogastrium (3). The functional results 2-4 months after operation were studied and compared by medical observers independently of the surgeons who had selected and performed the reconstructive procedures. Analysis of the functional results, and consideration of the degree to which the functional disorders associated with the various reconstructive procedures lend themselves to treatment, suggest that the Henley reconstructive procedure is the best, with the Roux-en-Y as a good second-best.  相似文献   
914.
915.
916.
917.
We present analytical and neuroprotective data on a unique spin trapping agent derived from a novel chemical class known as an azulenyl nitrone (AZN). Based on Colorimetric properties, AZN was used to assess the formation of free radicals in a bilateral carotid occlusion (BCO) model in gerbils by monitoring the conversion of the nitrone to the aldehyde in affected tissue. In addition, AZN was tested as a neuroprotectant in this model regarding the preservation of CA1 pyramidal cells of the hippocampus following transient ischemia/reperfusion. AZN was electrochemically oxidized to give the aldehyde using an HPLC system with on line electrochemical oxidation. The oxidation potential associated with a 50% loss of AZN occurred at about 600 mV (half-wave potential versus palladium electrode). The major product detected as AZN oxidation occurred in an aqueous methanolic medium was the corresponding azulenyl aldehyde. Oxidation of AZN was inversely related to the formation of the aldehyde. Based on this test, we considered the in vivo conversion of AZN to aldehyde to be a measurement of oxidative stress in tissue. Results show that 0.3% of hippocampal AZN was converted to aldehyde in animals treated as shams. However, in gerbils subjected to a 7-min ischemic insult plus 7-min reperfusion, the conversion rate was about 3 times higher at 1.0%. In this model, surviving CA1 hippocampal neurons were counted from gerbils that were subjected to 7 mins of BCO followed by 5 days of reperfusion. In sham animals, about 89 cells were counted in a selected field of CA1 neurons. With injury, only 27 cells on average survived (70% loss) and were counted from this selected field. Under similar conditions and AZN treatment, 57 cells survived (36% loss). We conclude, therefore, that the demonstrated neuroprotection occurs because AZN neutralizes radicals which contribute to neuronal damage following ischemia/reperfusion.  相似文献   
918.
919.
A study of two DNA polymorphisms (i2 RsaI, E237G) in the gene for the beta subunit of the IgE high affinity receptor (FcepsilonRIbeta) was performed in 168 Italian families with atopic asthmatic children. The prevalence of the E237G allele in the Italian population was 4%, so this polymorphism was unsuitable for this study. The i2 RsaI polymorphism minor allele frequency was 44%, and it had a PIC value of 0.37. Linkage analysis indicated a significant allele sharing in affected sib pairs for bronchial hyper-responsiveness (BHR, p=0.048), but not for allergic asthma. These data indicate an association of bronchial hyper-responsiveness with the FcepsilonRIbeta gene.  相似文献   
920.
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