首页 | 官方网站   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   584篇
  免费   31篇
医药卫生   615篇
  2023年   3篇
  2022年   7篇
  2021年   26篇
  2020年   18篇
  2019年   18篇
  2018年   32篇
  2017年   14篇
  2016年   16篇
  2015年   8篇
  2014年   22篇
  2013年   34篇
  2012年   33篇
  2011年   36篇
  2010年   20篇
  2009年   16篇
  2008年   30篇
  2007年   37篇
  2006年   30篇
  2005年   37篇
  2004年   17篇
  2003年   25篇
  2002年   18篇
  2001年   14篇
  2000年   11篇
  1999年   7篇
  1998年   2篇
  1997年   3篇
  1996年   3篇
  1993年   3篇
  1992年   4篇
  1990年   2篇
  1989年   4篇
  1988年   6篇
  1987年   3篇
  1986年   7篇
  1985年   4篇
  1984年   2篇
  1982年   2篇
  1980年   2篇
  1979年   3篇
  1978年   1篇
  1977年   4篇
  1976年   1篇
  1975年   4篇
  1974年   9篇
  1972年   3篇
  1970年   1篇
  1969年   1篇
  1967年   5篇
  1966年   4篇
排序方式: 共有615条查询结果,搜索用时 15 毫秒
81.
In order to assess the effects of dilazep on central hemodynamics and regional flows, 0.2 mg/kg of the drug were administered intravenously to 6 open-chest anesthetized dogs. Hemodynamic and flow measurements were performed under control conditions, and approximately 5, 10 and 25 min after treatment. Dilazep caused a marked and sustained reduction of coronary resistance and increased coronary blood flow. Flow increased uniformly in the subendocardial and subepicardial layers of the left ventricle so that no significant change occurred in the endo/epi flow ratio. Dilazep caused a significant reduction of total systemic resistance and aortic pressure, however flow to the liver, kidney and spleen was not reduced. We conclude that dilazep exerts a dilating action on the coronary and systemic arterial beds and increases uniformly regional myocardial blood flow. Dilazep does not alter the transmural distribution of coronary blood flow and does not impair kidney, liver and spleen perfusion.  相似文献   
82.
83.
84.
OBJECTIVES: To investigate the causes of attrition reported by obese patients treated by medical centres. DESIGN: Observational study. SETTING: Obese patients enrolled in a long-term study involving 18 Italian medical centres. PARTICIPANTS: A total of 940 obese patients (727 female; mean age, 49 years; mean BMI, 38.6 kg/m2). MEASUREMENTS: Causes of attrition reported by dropouts during a structured telephone interview. RESULTS: After a median observation period of 41 months (range, 25-50), 766 of 940 patients (81.5%) discontinued treatment. Sixty-two per cent of total dropout occurred in the first year of follow-up. Seventy-four per cent of dropouts reported a single primary reasons for treatment interruption. Two primary reasons were reported by 22.4% of patients, and three reasons by 3.4%. Practical difficulties, alone or in combination, were reported by more than half of dropouts (55%), and were the leading cause of attrition followed by perceived failure of treatment. Among practical difficulties, family problems or problems at work and logistics, coupled with health problems other than obesity, were the most frequent reasons of attrition, but also a perceived sense of abandonment or a bad interaction with therapists were frequently reported. CONCLUSION: Practical difficulties and psychological problems are the most important reasons of attrition reported by patients. A therapeutic alliance addressing these issues has a large potential to reduce treatment interruption and to improve outcome in obesity.  相似文献   
85.
Cryptosporidium sp. isolates from a waterborne outbreak of diarrhea in France were analyzed by PCR-restriction fragment length polymorphism analysis and sequencing of the Cpgp40/15 locus. Ninety-one percent of the isolates were Cryptosporidium hominis type Ib. The results of this study and those of studies of other outbreaks suggest that the type Ib allele is the predominant allele associated with waterborne cryptosporidiosis.  相似文献   
86.
Weight loss in men is commonly observed during prolonged high altitude exposure as a result of a daily negative energy balance. Its amount depends mainly on duration of exposure, altitude reached, and level of physical activity. This reduction in body weight often comes with a loss of muscular mass, likely contributing to the decreased physical performance generally reported. Limited data is, however, available on body composition, functional capacity, and cardiopulmonary response to exercise after high altitude exposure in women. The aim of this study was to evaluate the effects of prolonged high altitude exposure on body composition and on cardiopulmonary response to maximal exercise in a group of young, moderately active women. Twelve female subjects, aged 21.5 ± 3.1 (mean ± SD), BMI 22.1 ± 1.9 kg · m(-2) and Vo(2max) 33.8 ± 3.5 mL · kg(-1) · min(-1), participated in this study, by residing for 21 days at high altitude (5050 m, Pyramid, EV-K(2)-CNR laboratory). Before and after high altitude exposure, all subjects underwent both a body composition evaluation using two methods (bioimpedance analysis and DEXA) and a functional evaluation based on a maximal exercise test on a cycle ergometer with breath-by-breath gas analysis. After high altitude exposure, data showed a slight, nonsignificant reduction in body weight, with an average 3:2 reduction ratio between fat and fat-free mass evaluated by DEXA, in addition to a significant decrease in Vo(2max) on the cycle ergometer test (p<0.01). Changes in Vo(2max) correlated to changes of leg muscle mass, evaluated by DEXA (r(2) = 0.72; p<0.0001). No changes were observed in the maximal heart rate, work capacity, and ventilatory thresholds, while the Vo(2)/W slope was significantly reduced (p<0.05). Finally, Ve/Vo(2) and VE/Vco(2max) slopes were increased (p<0.01), suggesting a possible long-term modulation of the exercise ventilatory response after prolonged high altitude exposure.  相似文献   
87.
88.
89.
90.
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-23

京公网安备 11010802026262号