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   7002篇
  免费   8篇
  国内免费   1篇
电工技术   7篇
综合类   6篇
化学工业   105篇
金属工艺   4篇
机械仪表   8篇
建筑科学   36篇
矿业工程   3篇
能源动力   17篇
轻工业   56篇
水利工程   10篇
石油天然气   2篇
无线电   98篇
一般工业技术   121篇
冶金工业   6432篇
原子能技术   4篇
自动化技术   102篇
  2021年   7篇
  2019年   6篇
  2017年   3篇
  2016年   9篇
  2015年   4篇
  2013年   33篇
  2012年   20篇
  2011年   22篇
  2010年   19篇
  2009年   16篇
  2008年   18篇
  2007年   23篇
  2006年   17篇
  2005年   22篇
  2004年   12篇
  2003年   38篇
  2002年   21篇
  2001年   13篇
  2000年   17篇
  1999年   226篇
  1998年   2059篇
  1997年   1121篇
  1996年   818篇
  1995年   431篇
  1994年   352篇
  1993年   394篇
  1992年   51篇
  1991年   96篇
  1990年   55篇
  1989年   74篇
  1988年   65篇
  1987年   69篇
  1986年   73篇
  1985年   59篇
  1984年   8篇
  1983年   10篇
  1982年   34篇
  1981年   47篇
  1980年   75篇
  1979年   17篇
  1978年   21篇
  1977年   146篇
  1976年   323篇
  1975年   16篇
  1974年   5篇
  1973年   9篇
  1972年   7篇
  1971年   4篇
  1970年   4篇
  1955年   5篇
排序方式: 共有7011条查询结果,搜索用时 15 毫秒
1.
Electronic BITE is poor at identifying hardware failure and in present design approaches tends to create the reviled ‘unconfirmed failure’. A different approach to BITE and unconfirmed failure could improve both operational performance and the cost of maintenance.  相似文献   
2.
As an alternative to surgical splenectomy, partial splenic embolization was performed in seven children for hypersplenism manifested by splenomegaly, thrombocytopenia, leukopenia, and erythrocyte hemolysis. Within a few days, platelet and leukocyte counts rose significantly in all patients and were maintained in six of seven patients during a follow-up period of 9 to 69 months. Spleen size and abdominal distention also decreased significantly in all children. There were no infectious complications.  相似文献   
3.
4.
5.
6.
7.
8.
9.
We examined the ability of anti-human recombinant interleukin-2 (hu rIL-2) monoclonal antibody DMS-1.10 to increase serum half-life of hu rIL-2, and the effect of this complex on inhibition of tumor progression in a B16-F10 murine melanoma model. In C57B1/6 mice, intravenous (i.v.) injection of DMS-1.10 premixed with 1 x 10(4) units (U) of hu rIL-2 at a 1:1 molar ratio extended serum half-life greater than 10-fold (222 min) when compared to the same dose of hu rIL-2 alone (20 min). In a murine tumor model, multiple intraperitoneal (i.p.) injections of non-neutralizing DMS-1.10 premixed with hu rIL-2 at a 5:1 molar ratio reduced the growth rate of subcutaneous (s.c.) B16-F10 tumor in C57B1/6 mice by 64% when compared to PBS and irrelevant antibody treated controls. Although similar treatment with hu rIL-2 alone reduced tumor growth rate by 46%, it was significantly less effective than the premixed treatment. Results from a flow cytometry assay confirm B16-F10 does not have IL-2 receptors, precluding direct inhibition of tumor growth by hu rIL-2 treatments. We propose that therapeutic efficacy of hu rIL-2 is improved by prolonging the in vivo half-life with an anti-IL-2 antibody, thus augmenting hu rIL-2 bioactivity and enhancing the hosts immune response against tumor.  相似文献   
10.
INTRODUCTION: The aim of the study was the evaluation of the usefulness of transesophageal atrial pacing in predicting chronic oral treatment efficacy of symptomatic reciprocating supraventricular tachycardia in infants and in avoiding the risk of very dangerous recurrences at home. METHODS: We studied 13 infants (11 males, 2 females, mean age 43 +/- 31 days) with symptomatic reciprocating supraventricular tachycardia and no structural heart disease. All patients had chronic oral therapy, using the drug effective in acute i.v. somministration. Each patient was discharged when supraventricular tachycardia was not inducible with transesophageal atrial pacing after 5 half-lives of the drug used in chronic oral treatment. All patients, every 6 months, were retested with transesophageal atrial pacing alternatively during chronic oral therapy and after complete wash out. Oral therapy was stopped in each patient when supraventricular tachycardia was not inducible after the wash out. RESULTS: The number of oral treatments tested for each patient were 2 +/- 1 (range 1-5). The number of transesophageal studies performed for each patient were 4 +/- 2 (range 3-7). No patient had symptomatic episodes of supraventricular tachycardia or needed to change therapy during the follow-up. The oral treatment was stopped after the twelfth month of life in 8 patients and after the twenty-fourth in 2 others without recurrences. CONCLUSION: Transesophageal atrial pacing seems to be useful in predicting accurately and rapidly the oral treatment efficacy of supraventricular tachycardia in infants. Our protocol seems to be effective to avoid dangerous recurrences of tachycardia and to decide when we can stop therapy without risk.  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