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   10371篇
  免费   818篇
  国内免费   25篇
耳鼻咽喉   116篇
儿科学   244篇
妇产科学   159篇
基础医学   1170篇
口腔科学   267篇
临床医学   1116篇
内科学   1824篇
皮肤病学   95篇
神经病学   903篇
特种医学   391篇
外科学   1973篇
综合类   130篇
一般理论   5篇
预防医学   1047篇
眼科学   164篇
药学   898篇
中国医学   6篇
肿瘤学   706篇
  2023年   52篇
  2022年   134篇
  2021年   262篇
  2020年   161篇
  2019年   240篇
  2018年   297篇
  2017年   230篇
  2016年   240篇
  2015年   284篇
  2014年   402篇
  2013年   521篇
  2012年   830篇
  2011年   742篇
  2010年   415篇
  2009年   340篇
  2008年   571篇
  2007年   613篇
  2006年   547篇
  2005年   579篇
  2004年   521篇
  2003年   504篇
  2002年   426篇
  2001年   128篇
  2000年   116篇
  1999年   154篇
  1998年   88篇
  1997年   68篇
  1996年   65篇
  1995年   56篇
  1994年   52篇
  1993年   53篇
  1992年   82篇
  1991年   78篇
  1990年   80篇
  1989年   73篇
  1988年   68篇
  1987年   63篇
  1986年   65篇
  1985年   56篇
  1984年   81篇
  1983年   65篇
  1982年   46篇
  1981年   58篇
  1980年   45篇
  1979年   53篇
  1978年   64篇
  1977年   51篇
  1976年   58篇
  1974年   56篇
  1973年   60篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
R C Hunt  D M Bryan  V S Brinkley  T W Whitley  N H Benson 《JAMA》1991,265(15):1982-1984
This study assessed the capabilities of a traditional and an amplified stethoscope used by flight nurses to assess breath sound during air medical transport in an MBB BO-105 helicopter. We developed a normal breath sound model using a prerecorded tape of breath sounds interspersed with segments without breath sounds; the recorder had been placed in the chest wall of a resuscitation training manikin. Flight nurses completed control listening sessions in a quiet environment and experimental sessions during flight using a traditional stethoscope for half of the sessions and an amplified stethoscope for the remaining half. In the quiet environment, flight nurses accurately reported the presence or absence of breath sounds in 110 (92%) of 120 trials. During helicopter flight, none of the flight nurses heard breath sounds during any of the recorded segments with either the traditional stethoscope or the amplified stethoscope. We conclude that flight nurses are unable to hear normal breath sounds using a traditional or amplified stethoscope during flight in a medically configured MBB BO-105 helicopter. Improved stethoscopes, innovative methods of listening, and reduction of aircraft noise are potential solutions to the problems of breath sound assessment during air medical transport.  相似文献   
24.
We report on 7 patients (6 M, 1 F) with Coffin-Lowry syndrome who have a sensorineural hearing deficit in addition to developmental delay and characteristic facial changes. One of the patients also had a history of premature exfoliation of primary teeth. These are previously unappreciated clinical signs that may aid in the early diagnosis of Coffin-Lowry syndrome. Early diagnosis and recognition of a hearing deficit in the patient can lead to the use of hearing aids to help the patient achieve his or her full potential. These “;new”; clinical manifestations expand the phenotype of Coffin-Lowry syndrome and constitute an additional indication of pleiotropy. © 1993 Wiley-Liss, Inc.  相似文献   
25.
26.
27.
28.
29.
PURPOSE: Epilepsies in children are complex diseases. Guidelines are needed on the appropriate use of newer versus older anti-epileptic drugs (AEDs). This paper presents an individual patient-sampling model to assess the cost-effectiveness of using newer AEDs as add-on therapy in line with UK prescribing guidance. METHODS: Identification of the relevant parameters and treatment pathways for the model were achieved by a systematic review of the literature and discussions with clinical experts. Data were obtained from the literature and supplemented with data elicited from paediatric neurologists. The model considered paediatric patients over the period of childhood from the age of diagnosis to 18 years. RESULTS: The results suggest that the older and newer AEDs are similar in terms of drug retention rates and the average time in 'good' treatment outcomes. In terms of cost, the results indicate a consistent increase in cost (compared to older AEDs) when all of the newer AEDs are considered. The decision analysis results indicate that there are no important health benefits from the use of newer AEDs when used as add-on therapy. However, the analysis also reveals that the uncertainties in the model are greater than the differences between the drug strategies. CONCLUSIONS: To develop guidelines on the appropriate use of newer AEDs, better information is required from randomised controlled trials as there is insufficient data available in the public domain to accurately estimate the nature of the trade off between older versus newer AEDs.  相似文献   
30.
Objective. To provide national estimates of the effect of out-of-pocket premiums and benefits on Medicare beneficiaries' choice among managed care health plans.
Data Sources/Study Setting. The data represent the population of all Medicare+Choice (M+C) plans offered to Medicare beneficiaries in the United States in 1999.
Study Design. The dependent variable is the log of the ratio of the market share of the j th health plan to the lowest cost plan in the beneficiary's county of residence. The explanatory variables are measures of premiums and benefits in the j th health plan relative to the premiums and benefits in the lowest cost plan.
Data Collection Methods. The data are from the 1999 Medicare Compare database, and M+C enrollment data from the Centers for Medicare and Medicaid Services (CMS).
Principal Findings. A $10 increase in an M+C plan's out-of-pocket premium, relative to its competitors, is associated with a decrease of four percentage points in the j th plan's market share (i.e., from 25 to 21 percent), holding the premiums of competing plans constant.
Conclusions. Although our price elasticity estimates are low, the market share losses associated with small changes in a health plan's premium, relative to its competitors, may be sufficient to discipline premiums in a competitive market. Bidding behavior by plans in the Medicare Competitive Pricing Demonstration supports this conclusion.  相似文献   
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