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   4121篇
  免费   8篇
电工技术   3篇
综合类   2篇
化学工业   36篇
金属工艺   3篇
机械仪表   4篇
建筑科学   10篇
矿业工程   38篇
能源动力   2篇
轻工业   44篇
无线电   35篇
一般工业技术   36篇
冶金工业   3884篇
原子能技术   1篇
自动化技术   31篇
  2022年   2篇
  2021年   3篇
  2019年   7篇
  2018年   7篇
  2017年   6篇
  2016年   8篇
  2015年   10篇
  2014年   9篇
  2013年   18篇
  2012年   6篇
  2011年   7篇
  2010年   2篇
  2009年   6篇
  2008年   4篇
  2007年   8篇
  2006年   13篇
  2005年   4篇
  2004年   6篇
  2003年   12篇
  2002年   10篇
  2001年   9篇
  2000年   8篇
  1999年   141篇
  1998年   1242篇
  1997年   683篇
  1996年   425篇
  1995年   229篇
  1994年   186篇
  1993年   247篇
  1992年   31篇
  1991年   48篇
  1990年   48篇
  1989年   65篇
  1988年   66篇
  1987年   56篇
  1986年   37篇
  1985年   35篇
  1984年   2篇
  1983年   12篇
  1982年   21篇
  1981年   26篇
  1980年   23篇
  1979年   6篇
  1978年   9篇
  1977年   102篇
  1976年   201篇
  1975年   10篇
  1974年   3篇
  1973年   2篇
  1969年   2篇
排序方式: 共有4129条查询结果,搜索用时 15 毫秒
151.
Erb's type limb-girdle muscular dystrophy (LGMD) was identified and clinically studied in detail in a small community living in the Reunion Island (RI). It was linked to chromosome 15q and related to mutations in the muscle specific calpain 3 gene. A series of cases were afterwards clinically and genetically identified in the French metropolitan community. The phenotype was identical to the RI type in the great majority of cases, although clinical differences were noticed in a few cases. Six different mutations were identified in the RI families, whereas a series of 39 mutations were detected in the French metropolitan families, all different from those present in the RI patients. Phenotype-genotype correlations were attempted in both communities.  相似文献   
152.
OBJECTIVE: To estimate more precisely the risk of fetal loss and congenital abnormalities after maternal parvovirus B19 infection, and to assess the long term outcome for surviving infants. DESIGN: Prospective cohort study of pregnant women with confirmed B19 infection with follow up of the surviving infants. The rate of fetal loss in the study cohort was compared with that in pregnant women with varicella. SETTING: Cases reported by laboratories in England and Wales between 1985-1988 and 1992-1995. SAMPLE: Four hundred and twenty-seven pregnant women with B19 infection and 367 surviving infants of whom 129 were followed up at 7-10 years of age. METHODS: Questionnaires to obstetricians and general practitioners on outcome of pregnancy and health of surviving infants. Maternal infection confirmed by B19-specific IgM assay and/or IgG seroconversion. RESULTS: The excess rate of fetal loss in women with B19 infection was confined to the first 20 weeks of gestation and averaged 9%. Seven cases of fetal hydrops followed maternal infections between 9 and 20 weeks of gestation (observed risk 2.9%, 95% CI 1.2-5.9). No abnormalities attributable to B19 infection were found at birth in surviving infants (observed risk 0%, upper 95% CI 0.86%). No late effects were found at 7-10 years. CONCLUSIONS: Around 1 in 10 women infected before 20 weeks of gestation will suffer a fetal loss due to B19. The risk of an adverse outcome of pregnancy after this stage is remote. Infected women can be reassured that the maximum possible risk of a congenital abnormality due to B19 is under 1% and that long term development will be normal.  相似文献   
153.
Apoptosis is known as an active process of cell death forced by radio- and chemotherapy. Therefore, established concepts (terms, therapy schemes) will reflect a picture different from that usually seen, when examined under the apoptotic point of view. Furthermore, the development of new concepts for innovative diagnosis, prognosis and therapy could be accomplished. This is an attempt to reveal actual features of both aspects.  相似文献   
154.
155.
156.
157.
158.
159.
The rate of nitrosation of dihexylamine is enhanced when the reaction is carried ut in the presence of micelles containing bile acid conjugates or bile acid conjugates and lecithin. The nitrosation of smaller dialkylamines is not affected. The nitrosation of dihexylamine under these conditions is inhibited by alpha-tocopherol at pH 3 or pH 5. At pH 3 the reaction is inhibited by ascorbic acid, while at pH 5 it is inhibited by equimolar concentrations of ascorbic acid, but accelerated by higher concentration of ascorbic acid. The effect of ascorbic acid at pH 5 depends on the presence of oxygen and sulfamate.  相似文献   
160.
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