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   2770614篇
  免费   203102篇
  国内免费   8040篇
耳鼻咽喉   36410篇
儿科学   90157篇
妇产科学   74977篇
基础医学   388176篇
口腔科学   73518篇
临床医学   253625篇
内科学   553693篇
皮肤病学   64943篇
神经病学   231830篇
特种医学   105993篇
外国民族医学   744篇
外科学   414761篇
综合类   53223篇
现状与发展   5篇
一般理论   1253篇
预防医学   212789篇
眼科学   62024篇
药学   201031篇
  13篇
中国医学   5604篇
肿瘤学   156987篇
  2021年   23875篇
  2019年   24446篇
  2018年   33622篇
  2017年   25874篇
  2016年   29720篇
  2015年   33679篇
  2014年   46754篇
  2013年   69448篇
  2012年   93500篇
  2011年   98540篇
  2010年   59050篇
  2009年   56246篇
  2008年   91474篇
  2007年   97010篇
  2006年   98654篇
  2005年   94823篇
  2004年   90960篇
  2003年   87445篇
  2002年   84085篇
  2001年   130020篇
  2000年   132552篇
  1999年   112320篇
  1998年   33568篇
  1997年   29860篇
  1996年   29854篇
  1995年   28904篇
  1994年   26382篇
  1993年   24573篇
  1992年   86136篇
  1991年   82432篇
  1990年   79573篇
  1989年   76827篇
  1988年   70227篇
  1987年   68734篇
  1986年   64276篇
  1985年   61261篇
  1984年   45910篇
  1983年   38866篇
  1982年   23524篇
  1981年   21034篇
  1979年   39549篇
  1978年   28065篇
  1977年   23799篇
  1976年   22015篇
  1975年   23239篇
  1974年   27228篇
  1973年   25756篇
  1972年   24079篇
  1971年   22197篇
  1970年   20418篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
91.
92.
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   
93.
94.
95.
96.
97.
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   
98.
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   
99.
100.
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