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   2577346篇
  免费   189286篇
  国内免费   7535篇
耳鼻咽喉   34267篇
儿科学   85174篇
妇产科学   71585篇
基础医学   363112篇
口腔科学   69599篇
临床医学   233688篇
内科学   513265篇
皮肤病学   62437篇
神经病学   213221篇
特种医学   99834篇
外国民族医学   736篇
外科学   386003篇
综合类   50320篇
现状与发展   5篇
一般理论   969篇
预防医学   195310篇
眼科学   56562篇
药学   187847篇
  8篇
中国医学   5331篇
肿瘤学   144894篇
  2021年   19923篇
  2019年   20624篇
  2018年   29284篇
  2017年   22599篇
  2016年   26236篇
  2015年   29516篇
  2014年   40465篇
  2013年   60470篇
  2012年   80276篇
  2011年   84552篇
  2010年   51028篇
  2009年   49170篇
  2008年   79063篇
  2007年   83869篇
  2006年   85602篇
  2005年   81756篇
  2004年   78756篇
  2003年   76076篇
  2002年   73372篇
  2001年   128434篇
  2000年   131350篇
  1999年   110526篇
  1998年   31262篇
  1997年   27930篇
  1996年   28219篇
  1995年   27392篇
  1994年   25072篇
  1993年   23426篇
  1992年   85175篇
  1991年   81558篇
  1990年   78756篇
  1989年   76029篇
  1988年   69416篇
  1987年   67968篇
  1986年   63517篇
  1985年   60482篇
  1984年   44895篇
  1983年   37859篇
  1982年   22377篇
  1981年   19913篇
  1979年   38897篇
  1978年   27376篇
  1977年   23171篇
  1976年   21427篇
  1975年   22765篇
  1974年   26746篇
  1973年   25340篇
  1972年   23737篇
  1971年   21937篇
  1970年   20160篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
91.
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   
92.
93.
94.
95.
96.
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   
97.
Introduction: To increase students’ understanding of what it means to be a physician and engage in the everyday practice of medicine, a humanities program was implemented into the preclinical curriculum of the medical school curriculum. The purpose of our study was to determine how medical students’ views of being a doctor evolved after participating in a required humanities course.

Methods: Medical students completing a 16-clock hour humanities course from 10 courses were asked to respond to an open-ended reflection question regarding changes, if any, of their views of being a doctor. The constant comparative method was used for coding; triangulation and a variety of techniques were used to provide evidence of validity of the analysis.

Results: A majority of first- and second-year medical students (rr?=?70%) replied, resulting in 100 pages of text. A meta-theme of Contextualizing the Purpose of Medicine and three subthemes: the importance of Treating Patients Rather than a Disease, Understanding Observation Skills are Important, and Recognizing that Doctors are Fallible emerged from the data.

Conclusions: Results suggest that requiring humanities as part of the required preclinical curriculum can have a positive influence on medical students and act as a bridge to contextualize the purpose of medicine.  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