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   5091篇
  免费   278篇
  国内免费   31篇
耳鼻咽喉   54篇
儿科学   215篇
妇产科学   79篇
基础医学   412篇
口腔科学   154篇
临床医学   539篇
内科学   1303篇
皮肤病学   66篇
神经病学   232篇
特种医学   126篇
外国民族医学   1篇
外科学   1085篇
综合类   73篇
一般理论   1篇
预防医学   319篇
眼科学   117篇
药学   319篇
中国医学   27篇
肿瘤学   278篇
  2023年   37篇
  2022年   92篇
  2021年   185篇
  2020年   91篇
  2019年   149篇
  2018年   215篇
  2017年   123篇
  2016年   145篇
  2015年   138篇
  2014年   291篇
  2013年   298篇
  2012年   461篇
  2011年   495篇
  2010年   270篇
  2009年   200篇
  2008年   330篇
  2007年   328篇
  2006年   314篇
  2005年   237篇
  2004年   247篇
  2003年   210篇
  2002年   224篇
  2001年   31篇
  2000年   13篇
  1999年   27篇
  1998年   30篇
  1997年   28篇
  1996年   24篇
  1995年   17篇
  1994年   16篇
  1993年   16篇
  1992年   12篇
  1991年   9篇
  1990年   10篇
  1989年   7篇
  1988年   7篇
  1987年   3篇
  1986年   2篇
  1985年   7篇
  1984年   6篇
  1983年   3篇
  1982年   6篇
  1981年   5篇
  1980年   11篇
  1979年   3篇
  1977年   5篇
  1974年   4篇
  1972年   3篇
  1971年   2篇
  1962年   2篇
排序方式: 共有5400条查询结果,搜索用时 15 毫秒
81.
OBJECTIVE: Continuous positive airway pressure (CPAP) by face mask is an effective method of treating severe cardiogenic pulmonary edema (CPE). However, to our knowledge, no study has provided a precise evaluation of the effects of CPAP on cardiac function in patients presenting with CPE and preserved left ventricular (LV) function. DESIGN: Prospective observational clinical study. SETTING: A 14-bed, medical ICU at a university hospital. PATIENTS: Nine consecutive patients presenting with hypoxemic acute CPE. INTERVENTIONS: All patients were selected for 30 min of CPAP with 10 cm H(2)O by mask with fraction of inspired oxygen adjusted for a cutaneous saturation > 90%. Doppler echocardiography was performed before CPAP application and during the last 10 min of breathing with CPAP. Two-tailed, paired t-tests were used to compare data recorded at baseline (oxygen alone) and after CPAP. MEASUREMENTS AND RESULTS: Four patients presented CPE with preserved left ventricular (LV) function (a preserved LV ejection fraction [LVEF] > 45%, and/or aortic velocity time integral > 17 cm in the absence of aortic stenosis or hypertrophic cardiomyopathy). Oxygenation and ventilatory parameters were improved by CPAP in all patients. Hemodynamic monitoring and Doppler echocardiographic analysis demonstrated that in patients with preserved LV systolic function, mean arterial pressure and LV end-diastolic volume were decreased significantly by CPAP (p < 0.04). In patients with LV systolic dysfunction, CPAP improved LVEF (p < 0.05) and decreased LV end-diastolic volume (p = 0.001) significantly. CONCLUSION: CPAP improves oxygenation and ventilatory parameters in all kinds of CPE. In patients with preserved LV contractility, the hemodynamic benefit of CPAP results from a decrease in LV end-diastolic volume (preload).  相似文献   
82.
83.
84.
Introduction. Hepatitis C virus (HCV) infection affects almost 3% of the world''s population with the highest prevalence in Egypt (15%). The standard therapy; pegylated interferon (PEG-IFN) and ribavirin, is effective in only 60% of Egyptian patients; moreover it is costly, prolonged, and has severe side effects, so prediction of response is essential to reduce burden of unfavorable treatment. Several viral and host factors have been proved to affect response to the treatment PEG-IFN and ribavirin; the strongest of them is polymorphisms near IL28B; nonetheless, nonresponse in patients with favorable IL28B is still unexplained, which implies the importance of studying other immunological factors that may correlate with response. Interleukin 12 (IL-12) is one of the most important proinflammatory cytokine presented with the initiation of immune response, determining Th1 and Th2 differentiation. A functional single nucleotide polymorphism (A/C) at the 3′ untranslated region (3′UTR) at position 1188 (NCBI SNP database no 3212227) was reported to be associated with responding more efficiently to antiviral combination therapy in HCV genotype 1 infected patients. The present study aims to evaluate association between this polymorphism with fibrosis stages, necroinflammation activity, response to the combined therapy, and gender in Egyptian HCV genotype 4. Material and Methods. A total of 133 Egyptian chronic HCV (CHCV) patients were treated with IFN/RBV and were followed up. IL12B 1188 A/C genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PRC-RFLP) analysis. Results. A nonsignificant trend for higher sustained virological response (SVR) was observed in patients homozygote for IL12B 1188 A/C SNP CC genotype (69% SVR versus 30.8% NR) only but not in AC and AA genotypes. No association was detected between IL12B 1188 A/C polymorphism and less severe fibrosis or less liver activity. By stratification of response according to gender genotype, a significant difference in response between males and females was seen among AA genotype carriers only due to high number of non responder females. Conclusion. IL12B CC genotype appears to have some influence on SVR achievement but not on severe fibrosis and severe necroinflamation activity. Females carrying A/A genotype of IL12B 1188 A/C SNP achieve less SVR than those carrying AC and CC genotypes.  相似文献   
85.
86.
Clinical Oral Investigations - To analyze the retention forces between primary and secondary telescopic crowns milled from various materials and to compare them with the retention forces between...  相似文献   
87.
The International Journal of Cardiovascular Imaging - Cardiac resynchronization therapy (CRT) reduces the risk of ventricular arrhythmias (VA) in heart failure (HF) patients with left bundle branch...  相似文献   
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