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   3342篇
  免费   95篇
  国内免费   57篇
耳鼻咽喉   12篇
儿科学   171篇
妇产科学   58篇
基础医学   167篇
口腔科学   78篇
临床医学   109篇
内科学   734篇
皮肤病学   66篇
神经病学   105篇
特种医学   57篇
外科学   658篇
综合类   286篇
预防医学   90篇
眼科学   87篇
药学   160篇
中国医学   609篇
肿瘤学   47篇
  2024年   8篇
  2023年   27篇
  2022年   24篇
  2021年   59篇
  2020年   58篇
  2019年   338篇
  2018年   235篇
  2017年   117篇
  2016年   39篇
  2015年   54篇
  2014年   114篇
  2013年   65篇
  2012年   132篇
  2011年   116篇
  2010年   92篇
  2009年   51篇
  2008年   41篇
  2007年   49篇
  2006年   26篇
  2005年   18篇
  2004年   31篇
  2003年   18篇
  2002年   21篇
  2001年   28篇
  2000年   20篇
  1999年   16篇
  1998年   15篇
  1997年   9篇
  1996年   11篇
  1995年   10篇
  1994年   10篇
  1993年   10篇
  1992年   6篇
  1991年   6篇
  1990年   11篇
  1989年   4篇
  1988年   5篇
  1985年   122篇
  1984年   190篇
  1983年   151篇
  1982年   183篇
  1981年   156篇
  1980年   147篇
  1979年   137篇
  1978年   122篇
  1977年   89篇
  1976年   106篇
  1975年   74篇
  1974年   62篇
  1973年   60篇
排序方式: 共有3494条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
5.

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   
6.
7.
8.
9.
The Latin American population has a double way of immigration, one toward the United States by proximity and another toward Spain by sociocultural affinity. This population increase is affecting organ donation and transplantation in receiving countries.

Objective

To analyze the brain death (BD) concept knowledge in the Dominican Republic immigrant population in Florida (United States) and Spain.

Method

Population under study: Population born in the Dominican Republic, resident in Florida (United States) and in Spain. Inclusion criteria: Population older than 15 years stratified by age and sex. Assessment instrument: Donation attitude questionnaire PCID-DTO-Ríos. Fieldwork: Random selection based on stratification. Immigration support association collaboration in Florida and Spain was needed to locate potential respondents. Completion was anonymous and self-administered, with verbal consent.

Results

A total of 123 respondents, 57 residents in Spain and 66 in Florida, have been included in the study. The 27% (n = 33) of the respondents knowledgeable of the BD concept consider it the death of an individual. Of the remainder, 52% (n = 64) do not know about it, and the remaining 21% (n = 26) believe it does not mean the death of a patient. No differences were observed regarding migration countries (P > .05). There was no association of the BD concept with other psychosocial factors analyzed or with the attitude toward organ donation.

Conclusions

Knowledge of the BD concept among the Dominican immigrant population is similar in Spain and Florida, and, unlike most studies, there is no objective association with the attitude toward organ donation.  相似文献   
10.
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   
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