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   3409905篇
  免费   291562篇
  国内免费   13246篇
耳鼻咽喉   46756篇
儿科学   108902篇
妇产科学   89198篇
基础医学   545806篇
口腔科学   92766篇
临床医学   311423篇
内科学   601307篇
皮肤病学   91124篇
神经病学   292826篇
特种医学   133741篇
外国民族医学   288篇
外科学   522537篇
综合类   102103篇
现状与发展   24篇
一般理论   2360篇
预防医学   290913篇
眼科学   77780篇
药学   234358篇
  21篇
中国医学   9322篇
肿瘤学   161158篇
  2021年   54785篇
  2020年   34964篇
  2019年   57870篇
  2018年   71111篇
  2017年   53881篇
  2016年   59306篇
  2015年   73433篇
  2014年   107549篇
  2013年   172659篇
  2012年   93563篇
  2011年   94039篇
  2010年   116719篇
  2009年   121073篇
  2008年   81277篇
  2007年   84700篇
  2006年   94632篇
  2005年   90349篇
  2004年   91959篇
  2003年   82694篇
  2002年   72536篇
  2001年   102480篇
  2000年   95148篇
  1999年   95219篇
  1998年   64516篇
  1997年   62580篇
  1996年   60735篇
  1995年   56170篇
  1994年   50431篇
  1993年   47109篇
  1992年   67548篇
  1991年   64804篇
  1990年   61430篇
  1989年   60597篇
  1988年   56434篇
  1987年   55206篇
  1986年   52634篇
  1985年   52221篇
  1984年   48144篇
  1983年   44315篇
  1982年   41703篇
  1981年   39421篇
  1980年   37153篇
  1979年   40533篇
  1978年   35915篇
  1977年   32399篇
  1976年   29749篇
  1975年   28689篇
  1974年   30253篇
  1973年   29408篇
  1972年   27764篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
131.
132.
133.
134.
135.
136.
Coronary embolism (CE) is an uncommon and unique cause of acute myocardial infarction. In this report, we review 216 cases of CE including 2 new cases from our institution. The mean patient age was 52.5 years and 62% of the patients were males. Chest pain was the most common presenting symptom followed by dyspnea, and the most commonly affected vessel was the left anterior descending artery. Leading etiologies of the embolus were atrial fibrillation, septic emboli, and iatrogenic causes. Treatment approaches varied with thrombus aspiration being used in 30% of cases. In-hospital mortality rate was 36% and 13% of the cases were complicated by cerebrovascular accident. CE is a unique pathology that leads to acute myocardial infarction. It portends a high mortality rate and requires a high level of suspicion as symptoms may be misleading. Further research is needed in order to improve recognition and management and to lower associated mortality.  相似文献   
137.

Objectives

Despite evidence for increased musculoskeletal injury after concussion recovery, there is a lack of dynamic balance assessments that could inform management and research into this increased injury risk post-concussion. Our purpose was to identify tandem gait dynamic balance deficits in recreational athletes with a concussion history within the past 18-months compared to matched controls.

Design

Cross-sectional, laboratory study.

Methods

Fifteen participants with a concussion history (age: 19.7 ± 0.9 years; 9 females; median time since concussion 126 days, range 28–432 days), and 15 matched controls (19.7 ± 1.6 years; 9 females) with no recent concussion history participated. We measured center-of-pressure (COP) outcomes (velocity, path length, speed, dual-task cost) under 4 tandem gait conditions: (1) tandem gait, (2) tandem gait, eyes closed, (3) tandem gait, eyes open, cognitive distraction, and (4) tandem gait, eyes closed, cognitive distraction.

Results

The concussion history group demonstrated slower tandem gait velocity compared to the control group (4.0 cm/s difference), thus velocity was used as a covariate when analyzing COP path length and speed. The concussion history group (23.5%) demonstrated greater COP speed dual-task cost than the control group (16.3%) during the eyes closed dual-task condition. No other comparisons were statistically significant.

Conclusions

There may be subtle dynamic balance differences during tandem gait that are detectable after return-to-activity following concussion, but the clinical significance of these findings is unclear. Longitudinal investigations should identify acute movement deficits in varying visual and cognitive scenarios after concussion in comparison with recovery on traditional concussion assessment tools while also recording musculoskeletal injury outcomes.  相似文献   
138.
Academic output is just one aspect of a successful career as a plastic surgeon. However, for those with a strong interest in academia, the academic output of a department will likely be a key factor when deciding how to rank jobs. The aim of this study was to quantify and rank the academic output of plastic surgery units across the UK and Ireland. The Institute for Scientific Information (ISI) Web of Science Bibliometric analysis tool was used to collate cumulative (1950–2016), 10 year (2006–2016) and 3 years (2013–2015) research output data for plastic surgery units in the UK and Ireland. Sixty-six plastic surgery units were identified. Departments were ranked for each time period according to the number of papers produced, number of citations (Nc) and h-index (a measure of the impact of scientific output). The top 3 departments for number of papers in the last 10 years were The Royal Free Hospital, London (226) Broomfield Hospital, Chelmsford (218), and Morriston Hospital and Swansea (188). The top 3 for h-number were The Royal Free Hospital (21) Wythenshawe Hospital, Manchester (18) and Morriston Hospital (17). Academic output varies across plastic surgery units in the UK and Ireland. A number of departments have consistently maintained high academic outputs across the years and will be of interest to surgeons hoping to pursue a career in academia.  相似文献   
139.
There is a sharp difference in how one views TCR structure–function–behaviour dependent on whether its recognition of major histocompatibility complex‐encoded restriction elements (R) is germline selected or somatically generated. The generally accepted or Standard model is built on the assumption that recognition of R is by the V regions of the αβ TCR, which is not driven by allele specificity, whereas the competing model posits that recognition of R is allele‐specific. The establishing of allele‐specific recognition of R by the TCR would rule out the Standard model and clear the road to a consideration of a competing construct, the Tritope model. Here, the case for allele‐specific recognition (germline selected) is detailed making it obvious that the Standard model is untenable.  相似文献   
140.
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