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   2736194篇
  免费   190173篇
  国内免费   7559篇
耳鼻咽喉   35268篇
儿科学   91013篇
妇产科学   74251篇
基础医学   377896篇
口腔科学   71064篇
临床医学   245140篇
内科学   542344篇
皮肤病学   63048篇
神经病学   227593篇
特种医学   107845篇
外国民族医学   742篇
外科学   411838篇
综合类   52570篇
现状与发展   5篇
一般理论   970篇
预防医学   211410篇
眼科学   59189篇
药学   196375篇
  8篇
中国医学   5960篇
肿瘤学   159397篇
  2021年   20042篇
  2019年   20670篇
  2018年   48218篇
  2017年   37462篇
  2016年   43118篇
  2015年   30381篇
  2014年   41170篇
  2013年   61139篇
  2012年   86383篇
  2011年   102793篇
  2010年   67277篇
  2009年   59257篇
  2008年   96000篇
  2007年   102744篇
  2006年   86132篇
  2005年   83710篇
  2004年   81901篇
  2003年   80020篇
  2002年   75617篇
  2001年   128682篇
  2000年   131715篇
  1999年   110670篇
  1998年   31447篇
  1997年   28132篇
  1996年   28303篇
  1995年   27492篇
  1994年   25173篇
  1993年   23484篇
  1992年   85210篇
  1991年   81664篇
  1990年   78920篇
  1989年   76152篇
  1988年   69538篇
  1987年   68063篇
  1986年   63586篇
  1985年   60552篇
  1984年   44984篇
  1983年   37977篇
  1982年   22490篇
  1981年   19997篇
  1979年   38980篇
  1978年   27463篇
  1977年   23257篇
  1976年   21502篇
  1975年   22826篇
  1974年   26820篇
  1973年   25383篇
  1972年   23758篇
  1971年   21958篇
  1970年   20207篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
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   
82.
83.
84.
85.
86.
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   
87.
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   
88.
89.
90.
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