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   4520767篇
  免费   345851篇
  国内免费   17337篇
耳鼻咽喉   62380篇
儿科学   141382篇
妇产科学   120218篇
基础医学   681662篇
口腔科学   127144篇
临床医学   407470篇
内科学   817130篇
皮肤病学   112661篇
神经病学   373898篇
特种医学   176592篇
外国民族医学   688篇
外科学   688707篇
综合类   136335篇
现状与发展   27篇
一般理论   2594篇
预防医学   365616篇
眼科学   107891篇
药学   319488篇
  46篇
中国医学   14114篇
肿瘤学   227912篇
  2021年   57450篇
  2019年   59758篇
  2018年   75287篇
  2017年   57760篇
  2016年   64019篇
  2015年   77313篇
  2014年   111962篇
  2013年   177545篇
  2012年   124210篇
  2011年   128933篇
  2010年   126859篇
  2009年   128243篇
  2008年   114740篇
  2007年   122791篇
  2006年   130831篇
  2005年   125532篇
  2004年   126589篇
  2003年   116267篇
  2002年   105770篇
  2001年   171289篇
  2000年   166547篇
  1999年   152228篇
  1998年   72733篇
  1997年   68339篇
  1996年   65857篇
  1995年   61302篇
  1994年   55339篇
  1993年   51412篇
  1992年   110180篇
  1991年   105778篇
  1990年   101448篇
  1989年   99214篇
  1988年   91642篇
  1987年   89625篇
  1986年   85320篇
  1985年   83283篇
  1984年   69327篇
  1983年   61397篇
  1982年   48652篇
  1981年   45201篇
  1980年   42527篇
  1979年   60433篇
  1978年   48399篇
  1977年   43366篇
  1976年   39652篇
  1975年   40445篇
  1974年   44843篇
  1973年   43193篇
  1972年   40733篇
  1971年   37658篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
The present study aimed at examining the curative effect of modified posterior operation on treatment of Kümmell''s disease.About 30 patients of Kümmell''s disease with complete image and clinical data treated during June 2004 to July 2013 were conducted with anterior and posterior approaches, respectively. Kyphotic Cobb angle, fractured vertebra wedge angle, and the anterior and posterior heights of fractured vertebra were all measured through x-ray before and after operation, and the pain visual analog scale (VAS) was determined for evaluating the effect of operations. The injury and restoration of neurological function were assessed using Frankel classification.Patients in group A were treated with anterior operation, whereas group B was posterior operation. Postoperatively, VAS score, kyphotic Cobb angle, anterior vertebra height, and pathologic vertebra wedge angle were all significantly improved in patients with Kümmell''s disease receiving modified posterior operation (group B). Similar results were also observed in patients with anterior operation. The improvement of VAS and correction rate of kyphotic Cobb angle indicated equivalent effects of posterior and anterior operations. Meanwhile, alleviated neurological function damage was observed in 2 groups. Relevant factor analysis illustrated that there was no significant correlation of the severity and improvement rate of pain symptoms with age, medical history, anterior and posterior vertebra heights, kyphotic Cobb angle, and pathological vertebra wedge angle.Compared with traditional anterior approach, modified posterior operation, adopting transpedicular vertebral body grafting combined with vertebral pedicle screw fixation, could produce equivalent effects on kyphosis correction, pain relief, and improvement of neurological function in patients with Kümmell''s disease.  相似文献   
63.
64.
65.
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   
66.
Krishna S. Iyer 《Platelets》2020,31(4):474-482
Abstract

Platelets are small, anucleated effector cells that play an important role in linking the hemostatic and inflammatory processes in the body. Platelet function is known to be altered under various inflammatory conditions including aging. A gain in platelet function during aging can increase the risk of thrombotic events, such as stroke and acute myocardial infarction. Anti-platelet therapy is designed to reduce risk of serious cerebrovascular and cardiovascular events, but the adverse consequences of therapy, such as risk for bleeding increases with aging as well. Age-associated comorbidities such as obesity, diabetes, and hyperlipidemia also contribute to increased platelet activity and thus can enhance the risk of thrombosis. Therefore, identification of unique mechanisms of platelet dysfunction in aging and in age-associated comorbidities is warranted to design novel antiplatelet drugs. This review outlines some of the current areas of research on aging-related mechanisms of platelet hyperactivity and addresses the clinical urgency for designing anti-platelet therapies toward novel molecular targets in the aging population.  相似文献   
67.
68.
The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (Leq) measurements were collected during flight operations (Leq (flt ops)), non-flight operations (Leq (non-flt ops)), and over 24-hr periods (Leq (24-hr)). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH®) Threshold Limit Value (TLV®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The Leq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between Leq (flt ops), Leq (non-flt ops), and Leq (24-hr) and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) Leq (24-hr): 70.8–105.4 dBA; (2) Leq (flt ops): 70–101.2 dBA; and (3) Leq (non-flt ops): 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean Leqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The Leqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.  相似文献   
69.
70.
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