全文获取类型
收费全文 | 2913篇 |
免费 | 170篇 |
国内免费 | 3篇 |
专业分类
儿科学 | 124篇 |
妇产科学 | 44篇 |
基础医学 | 314篇 |
口腔科学 | 38篇 |
临床医学 | 450篇 |
内科学 | 669篇 |
皮肤病学 | 77篇 |
神经病学 | 255篇 |
特种医学 | 334篇 |
外科学 | 188篇 |
综合类 | 26篇 |
预防医学 | 233篇 |
眼科学 | 88篇 |
药学 | 103篇 |
中国医学 | 2篇 |
肿瘤学 | 141篇 |
出版年
2021年 | 17篇 |
2019年 | 31篇 |
2018年 | 48篇 |
2017年 | 25篇 |
2016年 | 31篇 |
2015年 | 33篇 |
2014年 | 48篇 |
2013年 | 72篇 |
2012年 | 84篇 |
2011年 | 75篇 |
2010年 | 100篇 |
2009年 | 84篇 |
2008年 | 113篇 |
2007年 | 126篇 |
2006年 | 118篇 |
2005年 | 96篇 |
2004年 | 90篇 |
2003年 | 113篇 |
2002年 | 73篇 |
2001年 | 68篇 |
2000年 | 53篇 |
1999年 | 62篇 |
1998年 | 64篇 |
1997年 | 84篇 |
1996年 | 74篇 |
1995年 | 58篇 |
1994年 | 66篇 |
1993年 | 59篇 |
1992年 | 65篇 |
1991年 | 47篇 |
1990年 | 48篇 |
1989年 | 85篇 |
1988年 | 81篇 |
1987年 | 74篇 |
1986年 | 68篇 |
1985年 | 63篇 |
1984年 | 35篇 |
1983年 | 44篇 |
1982年 | 30篇 |
1981年 | 41篇 |
1980年 | 33篇 |
1979年 | 28篇 |
1978年 | 36篇 |
1977年 | 20篇 |
1976年 | 24篇 |
1975年 | 27篇 |
1974年 | 17篇 |
1973年 | 25篇 |
1972年 | 31篇 |
1968年 | 20篇 |
排序方式: 共有3086条查询结果,搜索用时 0 毫秒
1.
2.
3.
Can Electrocardiographic Criteria Predict Adverse Cardiac Events and Positive Cardiac Markers? 总被引:5,自引:0,他引:5
Andra L. Blomkalns MD Christopher J. Lindsell PhD Abhinav Chandra MD Mary E. Osterlund MD W. Brian Gibler MD Charles V. Pollack MS MD Brian R. Tiffany MD PhD Judd E. Hollander MD James W. Hoekstra MD 《Academic emergency medicine》2003,10(3):205-210
OBJECTIVES: To determine electrocardiogram (ECG) predictors of positive cardiac markers and short-term adverse cardiac events in an undifferentiated chest pain population presenting to emergency departments (EDs). The authors hypothesized that specific ECG findings, other than those previously identified in higher-risk populations, would be predictive of cardiac outcomes and positive cardiac markers. METHODS: This study used data from a prospectively collected, retrospectively analyzed Internet-based data registry of undifferentiated chest pain patients (i*trACS). Logistic regression modeling was performed to determine the ECG findings that were predictive of 1) positive cardiac markers and 2) short-term adverse cardiac events. RESULTS: ST-segment elevation (STE), ST-segment depression (STD), pathological Q-waves (PQW), and T-wave inversion were associated with increased odds of percutaneous coronary intervention or catheterization, myocardial infarction, or coronary artery bypass grafting. The odds of creatine kinase-MB (CK-MB) measuring positive were increased if STE, STD, or PQW were present [odds ratio (OR) 2.495, 2.582, and 1.295, respectively]. A right bundle branch block tended to decrease the odds of CK-MB measuring positive (OR 0.658). A similar pattern of results was observed for troponin I (OR 3.608 for STE, 3.72 for STD, 1.538 for PQW). Troponin T showed an increased odds of measuring positive if any of STE, STD, left bundle branch block, or T-wave inversion were evident (OR 2.313, 2.816, 1.80, and 1.449, respectively). CONCLUSIONS: Initial ECG criteria can be used to predict short-term cardiac outcomes and positive cardiac markers. These findings can be important aids in the risk-stratification and aggressive treatment regimens of chest pain patients presenting to EDs. 相似文献
4.
Intestinal permeability is increased in several disorders such as Crohn's disease or rheumatoid arthritis. Since aging leads to alteration of many biological functions, the effect of aging on intestinal permeability was studied by measuring the intestinal permeability in aging rats gavaged with different size permeability probes--mannitol, polyethylene glycol (PEG) 400, and inulin. In rats fed with control diet, there was a significant increase in intestinal permeability to medium size probes PEG 400 (14.8 +/- 0.4 and 21.0 +/- 1.1% at 3 and 28 months respectively, p less than .01) and mannitol (3.41 +/- 0.4 and 5.3 +/- 0.5% at 3 and 28 months, respectively, p less than .01). Intestinal permeability of the large macromolecule inulin did not change (0.42 +/- 0.03 and 0.38 +/- 0.02% at 3 and 28 months, respectively) with aging. There was no correlation between weight of the rats and their intestinal permeability. Because dietary caloric restriction has been found to prolong the life span, retard deterioration of several biological functions, and affect intestinal absorptive functions, we examined the effect of lifelong calorie restriction on intestinal permeability changes. Lifelong calorie-restricted diet did not affect age-related change in intestinal permeability. We conclude that intestinal permeability of medium size probes increases with aging and that lifelong caloric restriction does not prevent this change. We speculate that age-associated deterioration in intestinal barrier functions could permit increased systemic absorption of lumenal antigens and could perhaps contribute to the genesis of antigen-related age-associated diseases. 相似文献
5.
6.
7.
8.
9.
10.