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   1977785篇
  免费   140399篇
  国内免费   3993篇
耳鼻咽喉   28530篇
儿科学   64880篇
妇产科学   57601篇
基础医学   285992篇
口腔科学   55572篇
临床医学   167989篇
内科学   388509篇
皮肤病学   41686篇
神经病学   155149篇
特种医学   77922篇
外国民族医学   672篇
外科学   307694篇
综合类   42223篇
现状与发展   1篇
一般理论   528篇
预防医学   145561篇
眼科学   45741篇
药学   147385篇
  1篇
中国医学   3888篇
肿瘤学   104653篇
  2018年   18926篇
  2016年   16115篇
  2015年   18466篇
  2014年   25995篇
  2013年   39763篇
  2012年   53942篇
  2011年   57786篇
  2010年   34594篇
  2009年   32678篇
  2008年   55622篇
  2007年   59788篇
  2006年   60692篇
  2005年   59472篇
  2004年   57114篇
  2003年   55437篇
  2002年   54549篇
  2001年   88103篇
  2000年   90542篇
  1999年   77345篇
  1998年   21921篇
  1997年   19815篇
  1996年   19942篇
  1995年   18718篇
  1994年   17815篇
  1993年   16650篇
  1992年   61864篇
  1991年   60459篇
  1990年   59461篇
  1989年   57538篇
  1988年   53729篇
  1987年   52702篇
  1986年   50423篇
  1985年   48145篇
  1984年   36066篇
  1983年   31090篇
  1982年   18681篇
  1981年   16427篇
  1979年   34058篇
  1978年   23946篇
  1977年   20522篇
  1976年   19424篇
  1975年   21359篇
  1974年   25266篇
  1973年   24303篇
  1972年   23124篇
  1971年   21515篇
  1970年   20249篇
  1969年   19217篇
  1968年   18230篇
  1967年   16289篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
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   
5.
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   
6.
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.  相似文献   
7.
8.
9.
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   
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