全文获取类型
收费全文 | 15765篇 |
免费 | 1285篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 103篇 |
儿科学 | 456篇 |
妇产科学 | 196篇 |
基础医学 | 2151篇 |
口腔科学 | 341篇 |
临床医学 | 1703篇 |
内科学 | 3000篇 |
皮肤病学 | 144篇 |
神经病学 | 1576篇 |
特种医学 | 618篇 |
外科学 | 2198篇 |
综合类 | 215篇 |
一般理论 | 32篇 |
预防医学 | 1886篇 |
眼科学 | 255篇 |
药学 | 1124篇 |
中国医学 | 22篇 |
肿瘤学 | 1068篇 |
出版年
2023年 | 133篇 |
2022年 | 178篇 |
2021年 | 506篇 |
2020年 | 308篇 |
2019年 | 428篇 |
2018年 | 484篇 |
2017年 | 373篇 |
2016年 | 399篇 |
2015年 | 473篇 |
2014年 | 593篇 |
2013年 | 819篇 |
2012年 | 1229篇 |
2011年 | 1225篇 |
2010年 | 748篇 |
2009年 | 615篇 |
2008年 | 1059篇 |
2007年 | 1005篇 |
2006年 | 974篇 |
2005年 | 958篇 |
2004年 | 871篇 |
2003年 | 783篇 |
2002年 | 656篇 |
2001年 | 168篇 |
2000年 | 118篇 |
1999年 | 128篇 |
1998年 | 144篇 |
1997年 | 102篇 |
1996年 | 98篇 |
1995年 | 78篇 |
1994年 | 71篇 |
1993年 | 58篇 |
1992年 | 95篇 |
1991年 | 73篇 |
1990年 | 71篇 |
1989年 | 81篇 |
1988年 | 77篇 |
1987年 | 92篇 |
1986年 | 63篇 |
1985年 | 59篇 |
1984年 | 59篇 |
1983年 | 52篇 |
1982年 | 40篇 |
1981年 | 30篇 |
1980年 | 30篇 |
1979年 | 36篇 |
1978年 | 42篇 |
1977年 | 27篇 |
1976年 | 28篇 |
1974年 | 42篇 |
1973年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Suzanne Christopher Tim Dunnagan George Haynes Lili Stiff 《Behavioral and brain functions : BBF》2007,3(1):10-9
Background
A multi-state consortium was developed in the US to conduct baseline data collection and intervention research on fetal alcohol syndrome. Each state employed support specialists whose job it was to reduce or eliminate alcohol consumption in women who were at high risk for drinking alcohol during their pregnancy. The purpose of this paper is to report how support specialists in three primarily rural/frontier states were trained to assess client need and how client need was actually assessed in the field. 相似文献62.
63.
Ana Teresa Timóteo Andreia Mamede Maria de Lurdes Ferreira José Serra José Alberto Oliveira Rui Cruz Ferreira Jorge Quininha 《Revista portuguesa de cardiologia》2007,26(2):135-143
BACKGROUND: Nitrate therapy can induce ischemic preconditioning with a consequent increase in tolerance to ischemia. In the context of acute coronary syndromes (ACS), nitrates may result in a different presentation. with greater protection. OBJECTIVES: To investigate in a population of patients with ACS whether previous chronic use of nitrates results in a different presentation of ACS. METHODS: We studied 287 patients (65 +/- 13 years, 66% male) admitted to our department in the first six months of 2005 with ACS (with and without ST-segment elevation). Of these, 8% were under nitrate therapy at the time of admission. In this group, 27% presented ACS without ST-segment elevation, while in the group without nitrates this value was 58% (p = 0.005). By univariate analysis, the use of nitrates was a predictor of the preferential occurrence of non-ST-segment elevation ACS (OR 0.27, 95% CI 0.10-0.71). After correction for the potential influence of variables (age, gender, previous revascularization and smoking) by multivariate logistic regression, nitrate therapy remained a borderline predictor of clinical presentation as non-ST-segment elevation ACS (OR 0.37, 95% CI 0.13-1.04, p = 0.059). CONCLUSIONS: Previous use of nitrates was associated with a tendency to present as non-ST-segment elevation ACS. This finding may be explained by the hypothesis that nitrates induce pharmacological preconditioning, reducing the transmural extent of myocardial infarction. 相似文献
64.
Kursad Erinc Mohamad H Yamani Randall C Starling Tim Crowe Robert Hobbs Corinne Bott-Silverman Gustavo Rincon James B Young Jingyuan Feng Daniel J Cook Nicholas Smedira E Murat Tuzcu 《The Journal of heart and lung transplantation》2005,24(8):1033-1038
BACKGROUND: Hypertension is a potential risk factor for allograft coronary vasculopathy. We evaluated the efficacy of angiotensin-converting enzyme (ACE) inhibitors and calcium antagonists, and their combined use, on the development of coronary vasculopathy in hypertensive heart transplant recipients. METHODS: Eighty-two heart transplant recipients underwent serial intravascular ultrasound (IVUS) analysis at baseline (within 1 month) and at 1 year after transplantation and were evaluated for the development of coronary vasculopathy. Patients were divided into 4 groups. Nineteen normotensive recipients received no treatment, control (Group A). Hypertensive patients were treated with either ACE inhibitors (Group B, n = 37), calcium antagonists (Group C, n = 16), or both (Group D, n = 10). RESULTS: We found a significant reduction in IVUS indices of coronary vasculopathy in heart transplant recipients who used a combination of an ACE inhibitor and a calcium antagonist compared with recipients who used either drug alone (p < 0.05). This synergistic efficacy was independent of the baseline indices evaluated in a multivariate regression analysis model and was noted despite comparable mean arterial pressure among the 3 hypertensive groups at 1 year, thus suggesting the presence of a synergistic anti-proliferative effect beyond the anti-hypertensive efficacy. CONCLUSIONS: The combined use of an ACE inhibitor and a calcium antagonist is more effective than the individual use of either drug alone on the development of coronary vasculopathy in cardiac transplant recipients. Large randomized clinical trials are warranted to evaluate such a synergistic efficacy. 相似文献
65.
66.
Evaluation of myocardial function in patients with end-stage heart failure during support with the Jarvik 2000 left ventricular assist device. 总被引:2,自引:0,他引:2
Markus Ferrari Kamuran A Kadipasaoglu Mihai Croitoru Jeff Conger Tim Myers Igor Gregoric Branislav Radovancevic George V Letsou O H Frazier 《The Journal of heart and lung transplantation》2005,24(2):226-228
In 2 patients with the Jarvik 2000 left ventricular assist device (LVAD), we assessed left ventricular systolic function through pressure-volume loops and E(max) at the beginning and end of the support period to potentially predict the possibility of pump removal without transplantation. Immediately before LVAD implantation and explantation, pressure and volume measurements were made with catheters and echocardiography, respectively, the E(max) being calculated from the slope of the pressure-volume loops, and the left ventricular ejection fraction (LVEF) being estimated by echocardiography. Transplantation was performed after 14 and 62 days, respectively, during which the LVEF increased by 75% (from 12% to 21%) in Patient 1 and remained unchanged (from 16% to 18%) in Patient 2, whereas the E(max) increased from 0.63 and 0.42 mm Hg/ml, respectively, to 1.31 and 1.07 mm Hg/ml, reflecting a 107% and 155% improvement. In these 2 cases, the E(max) was a more reliable indicator of intrinsic myocardial contractility than was the LVEF. 相似文献
67.
Tim Söderlund Ilkka Tulikoura Mika Niemelä Lauri Handolin 《European journal of trauma and emergency surgery》2009,35(5):455-462
Objective:
The aim of the present study was to characterise traumatic deaths occurring in the emergency room (ER) and to assess retrospectively the quality of given emergency care by evaluating whether any of the deaths could be identified as potentially preventable. 相似文献68.
69.
70.
Brian K Owler Shahan Momjian Zofia Czosnyka Marek Czosnyka Alonso Péna Neil G Harris Piotr Smielewski Tim Fryer Tim Donovan Jonathon Coles Adrian Carpenter John D Pickard 《Journal of cerebral blood flow and metabolism》2004,24(1):17-23
Regional cerebral blood flow (CBF) was studied with O(15)-water positron emission tomography and anatomic region-of-interest analysis on co-registered magnetic resonance in patients with idiopathic (n = 12) and secondary (n = 5) normal pressure hydrocephalus (NPH). Mean CBF was compared with values obtained from healthy volunteers (n = 12) and with clinical parameters. Mean CBF was significantly decreased in the cerebrum and cerebellum of patients with NPH. The regional analysis demonstrated that CBF was reduced in the basal ganglia and the thalamus but not in white matter regions. The results suggest that the role of the basal ganglia and thalamus in NPH may be more prominent than currently appreciated. The implications for theories regarding the pathogenesis of NPH are discussed. 相似文献