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   1338374篇
  免费   94464篇
  国内免费   2914篇
耳鼻咽喉   19750篇
儿科学   40320篇
妇产科学   38685篇
基础医学   187685篇
口腔科学   39844篇
临床医学   112854篇
内科学   262837篇
皮肤病学   30296篇
神经病学   106626篇
特种医学   53824篇
外国民族医学   435篇
外科学   208524篇
综合类   31049篇
现状与发展   6篇
一般理论   436篇
预防医学   92176篇
眼科学   31390篇
药学   100251篇
  4篇
中国医学   2991篇
肿瘤学   75769篇
  2018年   11792篇
  2015年   11926篇
  2014年   16758篇
  2013年   25319篇
  2012年   33112篇
  2011年   34989篇
  2010年   20806篇
  2009年   20285篇
  2008年   33691篇
  2007年   36788篇
  2006年   37369篇
  2005年   36108篇
  2004年   35202篇
  2003年   34170篇
  2002年   33683篇
  2001年   63692篇
  2000年   65393篇
  1999年   55456篇
  1998年   14690篇
  1997年   13490篇
  1996年   12964篇
  1995年   12246篇
  1994年   11491篇
  1992年   42811篇
  1991年   41338篇
  1990年   40601篇
  1989年   39605篇
  1988年   36988篇
  1987年   36454篇
  1986年   34938篇
  1985年   33150篇
  1984年   24840篇
  1983年   21078篇
  1982年   12689篇
  1981年   11580篇
  1980年   10784篇
  1979年   23942篇
  1978年   17088篇
  1977年   14841篇
  1976年   13393篇
  1975年   15284篇
  1974年   18095篇
  1973年   17578篇
  1972年   16823篇
  1971年   15724篇
  1970年   14921篇
  1969年   14363篇
  1968年   13470篇
  1967年   12019篇
  1966年   11264篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Degranulating mast cells are increased in the airway smooth muscle (ASM) of asthmatics, where they may influence ASM function. The aim of the present study was to determine whether histamine and tryptase modulate ASM cell granulocyte-macrophage colony-stimulating factor (GM-CSF) and RANTES (regulated on activation, normal T-cell expressed and secreted) release and also to examine which receptors are involved in this release. Confluent, quiescent ASM cells from asthmatic and nonasthmatic donors were treated with histamine (1 microM-100 microM) with and without histamine receptor antagonist pre-treatment, or the protease-activated receptor (PAR)-2 agonists tryptase (0.5-5 nM) and SLIGKV (100 and 400 microM). The cells were then stimulated with interleukin (IL)-1beta and/or tumour necrosis factor (TNF)-alpha (10 ng.mL(-1)) or left unstimulated for 24 h. Release of GM-CSF and RANTES was determined by ELISA and prostaglandin (PG)E(2) measured by enzyme immunoassay. Neither histamine nor tryptase induced ASM GM-CSF or RANTES secretion. However, histamine increased IL-1beta-induced GM-CSF release and markedly reduced TNF-alpha-induced RANTES release by both asthmatic and nonasthmatic cells to a similar extent, but did not modulate PGE(2) release. All changes involved activation of the histamine H1 receptor as they were partially or fully blocked by chlorpheniramine, but not ranitidine. Tryptase, via its proteolytic activity, also potentiated GM-CSF, but not RANTES, release from asthmatic and nonasthmatic ASM cells induced by both cytokines. PAR-2 involvement in the tryptase potentiation was unlikely because SLIGKV had no effect. In conclusion, mast cells, through histamine and tryptase, may locally modulate airway smooth muscle-induced inflammation in asthma.  相似文献   
992.
Objectives: Heavy smokers are a segment of the smoking population who are at increased risk of smoking-related morbidity and least likely to achieve cessation. This study identifies the impact of heavy smoking on quality of life by gender and describes the subpopulation for improved targeting.Methods: South Australian representative population data (n = 3010) was used to compare the health-related quality of life status of male and female heavy smokers as assessed by the SF-36.  相似文献   
993.
In a prospective, randomized multicenter trial, 175 patients with abdominal aortic aneurysms were treated by conventional operation. Two types of polyester prostheses (Gelsoft Plus, Vascute Terumo Corp., Hamburg, Germany or Microvel, Boston Scientific, Ratingen, Germany) were selected randomly for implantation. Diameters ranged from 14 to 20 mm. The diameters of the grafts were measured by ultrasound postoperatively, as well as 6, 12, and 24 months after operation. Local and systemic complications were recorded. Dilation of the main body of the “Gelsoft plus” prosthesis was 19% within the first 12 months and 30% for the Microvel prosthesis. Extreme dilation was not observed. Thus, vascular prostheses must be chosen small enough and the dilation of 20–30% should be considered. The most frequent complication was incisional hernia (32%).  相似文献   
994.
995.
996.
997.
998.
999.
1000.
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