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   846篇
  免费   11篇
电工技术   8篇
化学工业   68篇
金属工艺   1篇
机械仪表   2篇
建筑科学   2篇
矿业工程   1篇
能源动力   1篇
轻工业   31篇
水利工程   2篇
无线电   28篇
一般工业技术   17篇
冶金工业   687篇
自动化技术   9篇
  2017年   4篇
  2016年   4篇
  2014年   4篇
  2013年   7篇
  2012年   11篇
  2011年   8篇
  2010年   6篇
  2009年   4篇
  2008年   3篇
  2007年   4篇
  2006年   7篇
  2005年   2篇
  2004年   7篇
  2003年   7篇
  2002年   4篇
  2001年   2篇
  1999年   30篇
  1998年   197篇
  1997年   114篇
  1996年   80篇
  1995年   50篇
  1994年   32篇
  1993年   52篇
  1992年   18篇
  1991年   13篇
  1990年   8篇
  1989年   13篇
  1988年   8篇
  1987年   10篇
  1986年   7篇
  1985年   12篇
  1984年   2篇
  1983年   2篇
  1981年   4篇
  1980年   7篇
  1979年   2篇
  1977年   20篇
  1976年   40篇
  1973年   2篇
  1970年   4篇
  1966年   2篇
  1965年   3篇
  1964年   2篇
  1962年   2篇
  1961年   3篇
  1960年   6篇
  1958年   2篇
  1957年   2篇
  1956年   2篇
  1955年   2篇
排序方式: 共有857条查询结果,搜索用时 15 毫秒
51.
52.
The role of beta3- and other putative atypical beta-adrenoceptors in human white adipocytes and right atrial appendage has been investigated using CGP 12177 and novel phenylethanolamine and aryloxypropanolamine beta3-adrenoceptor (beta3AR) agonists with varying intrinsic activities and selectivities for human cloned betaAR subtypes. The ability to demonstrate beta1/2AR antagonist-insensitive (beta3 or other atypical betaAR-mediated) responses to CGP 12177 was critically dependent on the albumin batch used to prepare and incubate the adipocytes. Four aryloxypropanolamine selective beta3AR agonists (SB-226552, SB-229432, SB-236923, SB-246982) consistently elicited beta1/2AR antagonist-insensitive lipolysis. However, a phenylethanolamine (SB-220646) that was a selective full beta3AR agonist elicited full lipolytic and inotropic responses that were sensitive to beta1/2AR antagonism, despite it having very low efficacies at cloned beta1- and beta2ARs. A component of the response to another phenylethanolamine selective beta3AR agonist (SB-215691) was insensitive to beta1/2AR antagonism in some experiments. Because no [corrected] novel aryloxypropanolamine had a beta1/2AR antagonist-insensitive inotropic effect, these results establish more firmly that beta3ARs mediate lipolysis in human white adipocytes, and suggest that putative 'beta4ARs' mediate inotropic responses to CGP 12177. The results also illustrate the difficulty of predicting from studies on cloned betaARs which betaARs will mediate responses to agonists in tissues that have a high number of beta1- and beta2ARs or a low number of beta3ARs.  相似文献   
53.
54.
55.
The examination of alkaline phosphatase isoenzymes by means of isoelectric focusing in polyacrylamide gel rods using the apparatus and focusing method of Righetti and Drysdale is discussed. A simultaneous coupling procedure using alpha-naphthyl phosphate and fast blue salt R in 2-amino-2-methyl-1,3-propanediol buffer, pH 9.68, containing MgCl2 and ZnSO4 proved sensitive for developing the enzyme bands. Also discussed are the effects seen with the incorporation of Triton X100 into the gel and sample mixtures. Enzyme, which remained at the top of the gel without using this detergent, entered the gel easily with the addition of Triton X-100 into the application solution. Incorporation of Triton into the gel matrix resulted in some enzyme band patterns that showed distinct differences from gels containing no Triton.  相似文献   
56.
57.
The Buschke-Loewenstein tumor has a malignant clinical character but is histologically similar to the ordinary condyloma. The tumor grows deeply without invading the tissues, but compresses them and causes an intense inflammatory reaction. The diagnosis is clinical. Treatment with podophyllin and radiotherapy are not effective but bleomycin may be effective. Surgery is the accepted treatment and the extent of resection depends on the extent of the tumor.  相似文献   
58.
Seven normal male subjects performed 5-min bicycle exercise ranging from 50-100% maximum oxygen uptake at 4 ATA and three were also studied at 6 ATA. At all pressures, the subjects breathed 0.2 ATA O2 plus nitrogen. All subjects were able to perform maximum work at all pressures. No pressure-dependent variations in heart rate, O2 uptake, or CO2 output were noted. At both 4 and 6 ATA, ventilation was decreased at exercise levels greater than 80% maximum O2 uptake. The magnitude of the decrease was not great, however, and signified only minor CO2 retention. In some instances exercise ventilation closely approached the 15-S maximum breathing capacity and these subjects noted severe dyspnea, possibly due to dynamic compression of large airways. In three subjects, respiratory frequency was measured as well as minute ventilation; this relationship did not change with depth. Subjects performing heavy exercise at 6 ATA noted disturbances of consciousness, presumably due to N2 narcosis.  相似文献   
59.
60.
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