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   4889篇
  免费   4篇
电工技术   1篇
化学工业   17篇
金属工艺   4篇
机械仪表   8篇
建筑科学   4篇
矿业工程   1篇
能源动力   3篇
轻工业   10篇
无线电   5篇
一般工业技术   30篇
冶金工业   4787篇
原子能技术   3篇
自动化技术   20篇
  2020年   3篇
  2018年   4篇
  2017年   2篇
  2016年   6篇
  2013年   8篇
  2012年   2篇
  2011年   4篇
  2010年   4篇
  2009年   5篇
  2008年   1篇
  2006年   1篇
  2004年   3篇
  2003年   4篇
  2002年   3篇
  2001年   2篇
  2000年   1篇
  1999年   153篇
  1998年   1488篇
  1997年   858篇
  1996年   556篇
  1995年   326篇
  1994年   254篇
  1993年   303篇
  1992年   45篇
  1991年   64篇
  1990年   60篇
  1989年   73篇
  1988年   61篇
  1987年   68篇
  1986年   55篇
  1985年   64篇
  1984年   4篇
  1983年   9篇
  1982年   20篇
  1981年   18篇
  1980年   38篇
  1979年   1篇
  1978年   7篇
  1977年   91篇
  1976年   189篇
  1975年   8篇
  1974年   6篇
  1973年   3篇
  1972年   1篇
  1971年   7篇
  1970年   2篇
  1969年   1篇
  1965年   1篇
  1964年   1篇
  1963年   1篇
排序方式: 共有4893条查询结果,搜索用时 31 毫秒
41.
The Cuban recombinant vaccine against the hepatitis B virus was applied to a group of individuals over 65 from a geriatric home in Havana City. Dose of 20 ìg were administered within a scheme from 0.1 to 6 months in order to study its immunogenicity, which was evaluated at 2, 7, and 12 months after the first dose. 47.1% of protective titres and geometrical mean of 6.04 UI/L were obtained after 60 days. 100% of seroconversion (UI/L) and seroprotection (10 UI/L) and geometric mean of 136.93 UI/L were obtained when the immune response was evaluated on the 7th month. Finally, after a year, seroconversion and seroprotection were also of 100%, and the geometric mean was of 204.61 UI/L. It was proved the high immunogenic power of this vaccine, which makes it recommendable to protect this age group from the hepatitis B virus.  相似文献   
42.
43.
44.
Antral washouts have been widely used in the management of chronic sinusitis. With the advent of modern antibiotics and powerful topical nasal steroids, we sought to establish if a role remains for this procedure. One hundred and fourteen patients with chronic sinusitis were randomised into two groups. Patients in Group A received antral washouts followed by antibiotics and topical nasal steroids. Patients in the Group B received antibiotics and topical nasal steroids alone. In each group 51.6 per cent and 50 per cent of patients respectively improved with treatment. The outcome of treatment is also not influenced by endoscopic abnormality. The difference was not statistically significant (p = 0.86). The study indicates that half of patients with chronic sinusitis will improve with medical treatment but the addition of antral washout confers no additional benefits.  相似文献   
45.
46.
47.
Assembly of the higher-order structure of mitotic chromosomes is a prerequisite for proper chromosome condensation, segregation and integrity. Understanding the details of this process has been limited because very few proteins involved in the assembly of chromosome structure have been discovered. Using a human autoimmune scleroderma serum that identifies a chromosomal protein in human cells and Drosophila embryos, we cloned the corresponding Drosophila gene that encodes the homologue of vertebrate titin based on protein size, sequence similarity, developmental expression and subcellular localization. Titin is a giant sarcomeric protein responsible for the elasticity of striated muscle that may also function as a molecular scaffold for myofibrillar assembly. Molecular analysis and immunostaining with antibodies to multiple titin epitopes indicates that the chromosomal and muscle forms of titin may vary in their NH2 termini. The identification of titin as a chromosomal component provides a molecular basis for chromosome structure and elasticity.  相似文献   
48.
49.
A double-blind clinical study was performed to evaluate prednisolone as treatment for idiopathic feline lower urinary tract disease. No differences in response were observed in prednisolone- and placebo-treated cats.  相似文献   
50.
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