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   958871篇
  免费   65482篇
  国内免费   2471篇
耳鼻咽喉   13267篇
儿科学   29982篇
妇产科学   27323篇
基础医学   134301篇
口腔科学   26958篇
临床医学   79325篇
内科学   197840篇
皮肤病学   20463篇
神经病学   76639篇
特种医学   37793篇
外国民族医学   336篇
外科学   150092篇
综合类   19293篇
一般理论   271篇
预防医学   69749篇
眼科学   21213篇
药学   67700篇
中国医学   2011篇
肿瘤学   52268篇
  2019年   7468篇
  2018年   10960篇
  2017年   8281篇
  2016年   8874篇
  2015年   10548篇
  2014年   14246篇
  2013年   21963篇
  2012年   30892篇
  2011年   32344篇
  2010年   18955篇
  2009年   17502篇
  2008年   30452篇
  2007年   32222篇
  2006年   32568篇
  2005年   31792篇
  2004年   30192篇
  2003年   28977篇
  2002年   28462篇
  2001年   42452篇
  2000年   43971篇
  1999年   36975篇
  1998年   10142篇
  1997年   9277篇
  1996年   9220篇
  1995年   8572篇
  1994年   8183篇
  1993年   7677篇
  1992年   28308篇
  1991年   27076篇
  1990年   26475篇
  1989年   25418篇
  1988年   23601篇
  1987年   23215篇
  1986年   22307篇
  1985年   21216篇
  1984年   15891篇
  1983年   13532篇
  1982年   8156篇
  1979年   14625篇
  1978年   10243篇
  1977年   8661篇
  1976年   8177篇
  1975年   8981篇
  1974年   10729篇
  1973年   10206篇
  1972年   9666篇
  1971年   8928篇
  1970年   8596篇
  1969年   8037篇
  1968年   7687篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Graefe's Archive for Clinical and Experimental Ophthalmology - The published online version contains mistake as the author's first name and last name have been interchanged as "Hild...  相似文献   
2.
BACKGROUND The adenoma detection rate(ADR) is inversely associated with the incidence of interval colorectal cancer and serves as a benchmark quality criterion during screening colonoscopy. However, adenoma miss rates reach up to 26% and studies have shown that a second inspection of the right colon in retroflected view(RFV) can increase ADR.AIM To assess whether inspection of the whole colon in RFV compared to standard forward view(SFV) can increase ADR.METHODS Patients presenting for screening or surveillance colonoscopy were invited to participate in this randomized controlled trial and randomized into two arms. In RFV arm colonoscopy was initially performed with SFV, followed by a second inspection of the whole colon in RFV. In the SFV arm first withdrawal was performed with SFV, followed by a second inspection of the whole colon again with SFV. Number, size and morphology of polyps found during first and second inspection in each colonic segment were recorded and all polyps were removed and sent for histopathology in separate containers.RESULTS Two hundred and five patients were randomly assigned to the RFV(n = 101) and SFV(n = 104) arm. In the RFV arm, both polyp detection rate(PDR) and ADR were increased under second inspection in RFV(PDR 1~(st) SFV: 39.8%, PDR 2~(nd)RFV: 46.6%; ADR 1~(st) SFV: 35.2%, ADR 2~(nd) RFV: 42%). Likewise, in the SFV arm,PDR and ADR were increased under second inspection(PDR 1~(st) SFV: 37.5%, PDR 2~(nd) SFV: 46.6%; ADR 1~(st) SFV: 34.1%, ADR 2~(nd)SFV: 44.3%) with no significant differences in ADR and PDR between the SFV and RFV arm. Mean number of adenomas per patient(APP) was increased in the RFV and SFV(APP RFV arm: 1~(st) SFV: 1.71; 2~(nd) RFV: 2.38; APP SFV arm: 1~(st) SFV: 1.83, 2~(nd)SFV:2.2). The majority of adenomas additionally found during second inspection in RFV or in SFV were located in the transverse and left-sided colon and were 5 mm in size.CONCLUSION Second inspection of the whole colon leads to increased adenoma detection with no differences between SFV and RFV. Hence, increased detection is most likely a feature of the second inspection itself but not of the inspection mode.  相似文献   
3.
4.
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   
5.
6.
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   
7.
8.
Lasers in Medical Science - Studies reported the harmful effects of 2,4-D on body tissues, provoking changes in the anatomy and physiology of the kidneys, liver, and testicles. Thus, the objective...  相似文献   
9.
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