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   3232篇
  免费   95篇
  国内免费   57篇
耳鼻咽喉   12篇
儿科学   170篇
妇产科学   56篇
基础医学   165篇
口腔科学   76篇
临床医学   109篇
内科学   708篇
皮肤病学   63篇
神经病学   101篇
特种医学   55篇
外科学   586篇
综合类   304篇
预防医学   83篇
眼科学   83篇
药学   155篇
中国医学   612篇
肿瘤学   46篇
  2024年   7篇
  2023年   27篇
  2022年   22篇
  2021年   59篇
  2020年   58篇
  2019年   296篇
  2018年   198篇
  2017年   114篇
  2016年   39篇
  2015年   53篇
  2014年   117篇
  2013年   68篇
  2012年   132篇
  2011年   116篇
  2010年   92篇
  2009年   51篇
  2008年   42篇
  2007年   52篇
  2006年   27篇
  2005年   19篇
  2004年   32篇
  2003年   20篇
  2002年   24篇
  2001年   27篇
  2000年   20篇
  1999年   18篇
  1998年   15篇
  1997年   10篇
  1996年   11篇
  1995年   10篇
  1994年   11篇
  1993年   10篇
  1992年   6篇
  1991年   6篇
  1990年   11篇
  1989年   5篇
  1988年   5篇
  1985年   121篇
  1984年   183篇
  1983年   147篇
  1982年   178篇
  1981年   150篇
  1980年   144篇
  1979年   134篇
  1978年   118篇
  1977年   87篇
  1976年   103篇
  1975年   72篇
  1974年   59篇
  1973年   57篇
排序方式: 共有3384条查询结果,搜索用时 685 毫秒
1.
2.
3.
4.

Background

Pump speed optimization in patients implanted with a ventricular assist device represents a major challenge during the follow-up period. We present our findings on whether combined invasive hemodynamic ramp tests and cardiopulmonary exercise testing (CPX) can help optimize patient management.

Methods

Eighteen patients implanted with a HeartMate 3 (HM3) device underwent ramp tests with right heart catheterization (including central venous pressure [CVP], pulmonary artery pressure, pulmonary capillary wedge pressure [PCWP], and blood pressure) and echocardiography. Data were recorded at up to 4 speed settings. Speed changes were in steps of 200 revolutions/min (rpm). Evaluation of functional capacity by CPX was conducted according to the modified Bruce protocol.

Results

Only 30% of patients had normal PCWPs at their original rpm settings. In going from lowest to highest speeds, cardiac output improved by 0.25 ± 0.35 L/min/step (total change, 1.28 ± 0.3 L/min), and PCWP decreased by 1.9 ± 0.73 mm Hg/step (total change, 6 ± 1.6 mm Hg). CVP and systolic blood pressure did not change significantly with rpm. The rpm assessment was adjusted based on test results to achieve CVPs and PCWPs as close to normal limits as possible, which was feasible in all patients. On CPX, all patients demonstrated good performance (peak VO2, 16.8 ± 3.5 mL/kg/min).

Conclusion

Hemodynamic ramp testing provides an objective means of optimizing rpm, and has the potential to provide good exercise tolerance.  相似文献   
5.
6.
7.
8.
对四种同季不同产地采集的“三颗针”不同部位的四种生物碱进行了含量测定和分析,为该类药材的质量研究、生药采收、药厂选投料及开发应用等提供了科学依据。同时对该类资源的可持续利用也具有积极意义。  相似文献   
9.
The acute effects of the deposition of papain in the lungs of 4-month-old rabbits have been investigated with an amount not sufficient to cause emphysematous changes. During the first 2 days of in vivo deposition when hemorrhaging and inflammation occur, the total amounts of collagen and elastin in the lung, into which the papain had been instilled, did not change but the concentrations of collagen and elastin decreased 20 and 25% respectively. The rates of synthesis of collagen and other proteins doubled. By 4 weeks, collagen and elastin concentrations returned to, or were slightly above, control levels. The histological appearance and mean linear intercepts of lung sections and the compliance curves of excised lungs of the treated animals were similar to controls by 2 weeks after papain administration. The rabbit lung thus appears able to repair mild injury due to proteolytic enzymes.  相似文献   
10.
Two mediated smoking cessation programs were subjected to a field evaluation. The Quit Kit is a printed self-help package, and "Calling It Quits" consists of five segments which were aired on the local television news. A sample of 239 persons requested the Quit Kit and were followed. At the 2-month and 12-month follow-ups, respectively, 13.6% and 17.9% of those surveyed reported abstinence. Results indicate the potential of mediated interventions.  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