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   41862篇
  免费   4338篇
  国内免费   12篇
  2023年   164篇
  2021年   684篇
  2020年   508篇
  2019年   605篇
  2018年   731篇
  2017年   666篇
  2016年   1115篇
  2015年   1844篇
  2014年   2002篇
  2013年   2471篇
  2012年   3061篇
  2011年   2934篇
  2010年   1963篇
  2009年   1689篇
  2008年   2367篇
  2007年   2365篇
  2006年   2256篇
  2005年   2013篇
  2004年   1993篇
  2003年   1793篇
  2002年   1769篇
  2001年   676篇
  2000年   622篇
  1999年   645篇
  1998年   465篇
  1997年   370篇
  1996年   330篇
  1995年   366篇
  1994年   329篇
  1993年   329篇
  1992年   435篇
  1991年   370篇
  1990年   358篇
  1989年   372篇
  1988年   376篇
  1987年   341篇
  1986年   283篇
  1985年   305篇
  1984年   314篇
  1983年   274篇
  1982年   265篇
  1981年   238篇
  1980年   220篇
  1979年   223篇
  1978年   188篇
  1977年   191篇
  1976年   199篇
  1975年   202篇
  1974年   168篇
  1973年   172篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
71.
72.
Saphenous vein ligation and stripping was performed on 27 patients in the immediate postpartum period without complications. Doing the operation at this time saves time and money. Technically it is easier to do postpartum than during pregnancy, and the patients have less postoperative discomfort than is usual with phlebectomy at other times.  相似文献   
73.
Elucidating the causal mechanisms responsible for disease can reveal potential therapeutic targets for pharmacological intervention and, accordingly, guide drug repositioning and discovery. In essence, the topology of a network can reveal the impact a drug candidate may have on a given biological state, leading the way for enhanced disease characterization and the design of advanced therapies. Network-based approaches, in particular, are highly suited for these purposes as they hold the capacity to identify the molecular mechanisms underlying disease. Here, we present drug2ways, a novel methodology that leverages multimodal causal networks for predicting drug candidates. Drug2ways implements an efficient algorithm which reasons over causal paths in large-scale biological networks to propose drug candidates for a given disease. We validate our approach using clinical trial information and demonstrate how drug2ways can be used for multiple applications to identify: i) single-target drug candidates, ii) candidates with polypharmacological properties that can optimize multiple targets, and iii) candidates for combination therapy. Finally, we make drug2ways available to the scientific community as a Python package that enables conducting these applications on multiple standard network formats.  相似文献   
74.
Ultraviolet light irradiation of bacterial spores in the presence of hydrogen peroxide has been shown to produce synergistic kills when compared with ultraviolet light (u.v.) and hydrogen peroxide used sequentially. This use in combination has been patented for the commercial sterilization of packaging before filling with UHT-processed products. Previous results have shown that lamps producing u.v. light with a maximum output at about 254 nm were extremely effective. Results obtained using a Synchrotron radiation source to produce a narrow band of irradiation now shows that the greatest kill of spores of Bacillus subtilis in the presence of hydrogen peroxide is obtained with radiation at ˜270 nm. Such results suggest that the action of the u.v. light is not directly on the spore DNA but may be related to the production of free hydroxyl radicals from hydrogen peroxide.  相似文献   
75.
76.
77.
78.
79.
In the South-west Thames Region 2619 patients (2105 women and 514 men) were discharged with a diagnosis of femoral neck fracture in 1974. The equivalent of a 250-bedded hospital was occupied throughout the year. The incidence, average length of stay, and mortality rate rose with increasing age and there were differences in these indices in the five health areas. These results confirm the enormous burden placed on the hospital service by patients with fracture of the femoral neck but suggest that differences in practice in the five areas may contribute to the size of the problem.  相似文献   
80.
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