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   3048篇
  免费   253篇
  国内免费   12篇
耳鼻咽喉   19篇
儿科学   73篇
妇产科学   62篇
基础医学   442篇
口腔科学   45篇
临床医学   326篇
内科学   702篇
皮肤病学   17篇
神经病学   234篇
特种医学   311篇
外科学   291篇
综合类   45篇
一般理论   1篇
预防医学   411篇
眼科学   46篇
药学   203篇
中国医学   1篇
肿瘤学   84篇
  2021年   37篇
  2020年   24篇
  2019年   35篇
  2018年   35篇
  2017年   41篇
  2016年   33篇
  2015年   43篇
  2014年   71篇
  2013年   80篇
  2012年   114篇
  2011年   117篇
  2010年   72篇
  2009年   73篇
  2008年   133篇
  2007年   139篇
  2006年   125篇
  2005年   104篇
  2004年   103篇
  2003年   116篇
  2002年   101篇
  2001年   125篇
  2000年   111篇
  1999年   98篇
  1998年   48篇
  1997年   49篇
  1996年   42篇
  1995年   39篇
  1994年   51篇
  1993年   42篇
  1992年   80篇
  1991年   72篇
  1990年   80篇
  1989年   86篇
  1988年   88篇
  1987年   68篇
  1986年   62篇
  1985年   67篇
  1984年   62篇
  1983年   50篇
  1982年   30篇
  1981年   38篇
  1980年   35篇
  1979年   29篇
  1978年   31篇
  1977年   24篇
  1976年   30篇
  1975年   16篇
  1974年   25篇
  1973年   16篇
  1972年   15篇
排序方式: 共有3313条查询结果,搜索用时 31 毫秒
101.
This study follows a group of 174 young people with new onset of schizotypal symptoms and examines factors which may lead to conversion to psychosis. These prodromal subjects were screened for symptoms and later given the Structured Clinical Interview of DSM-III-R at one year, two years and ten years post onset. We also included the Paranoia Scale of Fenigstein and Vanable and the Scale for Thought, Language and Communications of Andreasen in all interviews. Our analysis found that the addition of scales for paranoia and thought disorder enhanced prediction of conversion to psychosis and long term outcome. The early occurrence of ideas of reference and poverty of thought appear to be significant predictors of future deterioration even when considered among other high-risk variables.  相似文献   
102.
103.
104.
105.
106.
Wilcox CS 《Hypertension》2012,59(2):375-381
Plasma levels of asymmetric dimethylarginine or markers of reactive oxygen species are increased in subjects with risk factors for cardiovascular disease or chronic kidney disease. We tested the hypothesis that reactive oxygen species generate cellular asymmetric dimethylarginine that together cause endothelial dysfunction that underlies the risk of subsequent disease. Rat preglomerular vascular smooth muscle cells transfected with p22(phox) had increased NADPH oxidase activity, enhanced activity and expression of protein arginine methyltransferase, and reduced activity and protein expression of dimethylarginine dimethylaminotransferase and of cationic amino acid transferase 1 resulting in increased cellular levels of asymmetric dimethylarginine. Rats infused with angiotensin II had oxidative stress. The endothelial function of their mesenteric arterioles was changed from vasodilatation to vasoconstriction, accompanied by increased vascular asymmetric dimethylarginine. All of these changes were prevented by Tempol. In vivo silencing of dimethylarginine dimethylaminotransferase 1 increased plasma levels of asymmetric dimethylarginine, whereas silencing of dimethylarginine dimethylaminotransferase 2 impaired endothelial function. We suggest that initiation factors, such as angiotensin II, expressed in blood vessels or tissues of subjects with cardiovascular and kidney disease risk factors generate reactive oxygen species from NADPH oxidase that enhances cellular asymmetric dimethylarginine in an amplification loop. This leads to adverse changes in vascular and organ functions, as a consequence of reduced tissue levels of NO and increased reactive oxygen species. Thus, we conclude that reactive oxygen species and asymmetric dimethylarginine form a tightly coupled amplification system that translates cardiovascular/kidney risk into overt disease.  相似文献   
107.
Acute exacerbations of interstitial lung disease present as clinical deteriorations, with progressive hypoxemia and parenchymal consolidation not related to infection, heart failure or thromboembolic disease. Following single lung transplantation, patients receive maintenance immunosuppression, which could mitigate the development of acute exacerbations in the native lung. A 66-year-old man with fibrotic, nonspecific interstitial pneumonitis presented with fever, hypoxemia and parenchymal consolidation limited to the native lung four years after single lung transplantation. Investigations were negative for infection, heart failure and thromboembolic disease. The patient worsened over the course of one week despite broad-spectrum antimicrobial therapy, but subsequently improved promptly with augmentation of prednisone dosed to 50 mg daily and addition of N-acetylcysteine. Hence, the patient fulfilled the criteria for a diagnosis of an acute exacerbation of pulmonary fibrosis in his native lung. Clinicians should consider acute exacerbation of parenchymal lung disease of the native lung in the differential diagnosis of progressive respiratory deterioration following single lung transplantation for pulmonary fibrosis.  相似文献   
108.
109.
110.
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