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   3364431篇
  免费   245489篇
  国内免费   8405篇
耳鼻咽喉   45354篇
儿科学   110880篇
妇产科学   94108篇
基础医学   479122篇
口腔科学   93807篇
临床医学   310501篇
内科学   657534篇
皮肤病学   78945篇
神经病学   275889篇
特种医学   128669篇
外国民族医学   964篇
外科学   495897篇
综合类   69027篇
现状与发展   7篇
一般理论   1447篇
预防医学   265641篇
眼科学   75882篇
药学   245957篇
  12篇
中国医学   6464篇
肿瘤学   182218篇
  2019年   26430篇
  2018年   36767篇
  2017年   28336篇
  2016年   32416篇
  2015年   36828篇
  2014年   50718篇
  2013年   76912篇
  2012年   102329篇
  2011年   108554篇
  2010年   64986篇
  2009年   62481篇
  2008年   101925篇
  2007年   108437篇
  2006年   109653篇
  2005年   105758篇
  2004年   101796篇
  2003年   98115篇
  2002年   94817篇
  2001年   156291篇
  2000年   159945篇
  1999年   135101篇
  1998年   39154篇
  1997年   34967篇
  1996年   35425篇
  1995年   34079篇
  1994年   31419篇
  1993年   29474篇
  1992年   106246篇
  1991年   103124篇
  1990年   99912篇
  1989年   96443篇
  1988年   88940篇
  1987年   87164篇
  1986年   82171篇
  1985年   78308篇
  1984年   58900篇
  1983年   50243篇
  1982年   29963篇
  1981年   26933篇
  1979年   53028篇
  1978年   37959篇
  1977年   32209篇
  1976年   29790篇
  1975年   31905篇
  1974年   38012篇
  1973年   36665篇
  1972年   34517篇
  1971年   32089篇
  1970年   29858篇
  1969年   28501篇
排序方式: 共有10000条查询结果,搜索用时 254 毫秒
101.
102.
103.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
104.
105.
106.
107.
108.
In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti–β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation.  相似文献   
109.
Animal and human studies suggest fish oil and green tea may have protective effect on prostate cancer. Fatty acid synthase (FAS) has been hypothesized to be linked to chemoprotective effects of both compounds. This study evaluated the independent and joint effects of fish oil (FO) and green tea supplement (epigallocatechin-3-gallate, EGCG) on FAS and Ki-67 levels in prostate tissue. Through a double-blinded, randomized controlled trial with 2 × 2 factorial design, 89 men scheduled for repeat prostate biopsy following an initial negative prostate biopsy were randomized into either FO alone (1.9 g DHA + EPA/day), EGCG alone (600 mg/day), a combination of FO and EGCG, or placebo. We used linear mixed-effects models to test the differences of prostate tissue FAS and Ki-67 by immunohistochemistry between pre- and post-intervention within each group, as well as between treatment groups. Results did not show significant difference among treatment groups in pre-to-post-intervention changes of FAS (P = 0.69) or Ki-67 (P = 0.26). Comparing placebo group with any of the treatment groups, we did not find significant difference in FAS or Ki-67 changes (all P > 0.05). Results indicate FO or EGCG supplementation for a short duration may not be sufficient to produce biologically meaningful changes in FAS or Ki-67 levels in prostate tissue.  相似文献   
110.
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