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   2641437篇
  免费   189724篇
  国内免费   11629篇
耳鼻咽喉   34607篇
儿科学   85652篇
妇产科学   72116篇
基础医学   369677篇
口腔科学   70647篇
临床医学   242079篇
内科学   522966篇
皮肤病学   62911篇
神经病学   216049篇
特种医学   101842篇
外国民族医学   778篇
外科学   391442篇
综合类   60625篇
现状与发展   24篇
一般理论   969篇
预防医学   199759篇
眼科学   58345篇
药学   193899篇
  46篇
中国医学   8803篇
肿瘤学   149554篇
  2021年   23128篇
  2019年   22449篇
  2018年   31319篇
  2017年   24320篇
  2016年   27907篇
  2015年   32141篇
  2014年   43688篇
  2013年   63081篇
  2012年   84201篇
  2011年   88959篇
  2010年   53608篇
  2009年   51288篇
  2008年   81727篇
  2007年   86532篇
  2006年   88293篇
  2005年   84464篇
  2004年   80494篇
  2003年   77716篇
  2002年   74729篇
  2001年   129468篇
  2000年   132470篇
  1999年   111723篇
  1998年   32115篇
  1997年   28736篇
  1996年   28842篇
  1995年   27974篇
  1994年   25570篇
  1993年   23715篇
  1992年   85506篇
  1991年   81841篇
  1990年   79045篇
  1989年   76272篇
  1988年   69679篇
  1987年   68152篇
  1986年   63666篇
  1985年   60603篇
  1984年   44983篇
  1983年   37977篇
  1982年   22470篇
  1981年   20001篇
  1979年   38969篇
  1978年   27439篇
  1977年   23252篇
  1976年   21495篇
  1975年   22813篇
  1974年   26787篇
  1973年   25372篇
  1972年   23749篇
  1971年   21955篇
  1970年   20183篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
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   
7.
8.
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   
9.
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   
10.
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