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   3134978篇
  免费   227455篇
  国内免费   8391篇
耳鼻咽喉   43026篇
儿科学   99903篇
妇产科学   85696篇
基础医学   441361篇
口腔科学   88500篇
临床医学   285053篇
内科学   616530篇
皮肤病学   73692篇
神经病学   255971篇
特种医学   120959篇
外国民族医学   800篇
外科学   475772篇
综合类   63023篇
现状与发展   5篇
一般理论   1146篇
预防医学   235916篇
眼科学   71042篇
药学   231683篇
  10篇
中国医学   6559篇
肿瘤学   174177篇
  2019年   24098篇
  2018年   34304篇
  2017年   26400篇
  2016年   30553篇
  2015年   34415篇
  2014年   47238篇
  2013年   70655篇
  2012年   93851篇
  2011年   99202篇
  2010年   59692篇
  2009年   57318篇
  2008年   93324篇
  2007年   98933篇
  2006年   100825篇
  2005年   96739篇
  2004年   93202篇
  2003年   89769篇
  2002年   87010篇
  2001年   155623篇
  2000年   159606篇
  1999年   134664篇
  1998年   37547篇
  1997年   33161篇
  1996年   33401篇
  1995年   32275篇
  1994年   29626篇
  1993年   27729篇
  1992年   104469篇
  1991年   100364篇
  1990年   97349篇
  1989年   94039篇
  1988年   86130篇
  1987年   84417篇
  1986年   79121篇
  1985年   75561篇
  1984年   55908篇
  1983年   47351篇
  1982年   27357篇
  1981年   24335篇
  1979年   49470篇
  1978年   34448篇
  1977年   29464篇
  1976年   26948篇
  1975年   28855篇
  1974年   34295篇
  1973年   32483篇
  1972年   30491篇
  1971年   28405篇
  1970年   26464篇
  1969年   25331篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
OBJECTIVE: Neighborhood sociodemographic characteristics may be important to the mental health of older adults who have decreased mobility and fewer resources. Our objective was to examine the association between neighborhood context and level of depressive symptomatology in older adults in a diverse geographic region of central North Carolina. METHODS: The sample included 2,998 adults 65 or older residing in 91 census tracts. Depressive symptoms were measured using the Center for Epidemiologic Studies-Depression scale (CES-D). Neighborhoods were characterized by five census-based characteristics: socioeconomic disadvantage, socioeconomic advantage, racial/ethnic heterogeneity, residential stability, and age structure. RESULTS: In ecologic level analyses, level of census tract socioeconomic disadvantage was associated with increased depressive symptoms. To determine whether neighborhood context was associated with depressive symptoms independently of individual characteristics, the authors used multilevel modeling. The authors examined the ability of each of five neighborhood (level 2) characteristics to predict a level 1 outcome (CES-D symptoms) controlling for the effects of individual (level 1) characteristics. Younger age, being widowed, lower income, and having some functional limitations were associated with increased depression symptoms conditional on census tract random effects. However, none of the neighborhood characteristics was significantly associated with depression symptoms, conditional on census tract random effects, either unadjusted or adjusted for individual characteristics. CONCLUSION: Any observed association between neighborhood sociodemographic characteristics and individual depressive symptoms in our sample may reflect the characteristics of the individuals who reside in the neighborhood rather than the neighborhood characteristics themselves. The use of multilevel modeling is important to separate these effects.  相似文献   
993.
994.
995.
996.
Abstract Migraine without aura is typically considered a female condition. The purpose of this study was to determine if there have been any changes in the female-to-male ratio of the disease over time. We included in the study all patients with migraine without aura (n=3457) referred to the Parma University Headache Centre between 1976 and 1995. They were divided into subgroups with respect to gender and year-range of onset of migraine (before 1960, in the 1960s, in the 1970s, in the 1980s, and between 1990 and 1995). Gender ratio ranged from 3.6:1 (in patients with onset before 1960) to 2.8:1 (in patients with onset in the 1980s), with no statistically significant changes during the observation period.  相似文献   
997.
Social phobia, fear of negative evaluation and harm avoidance.   总被引:1,自引:0,他引:1  
This naturalistic, prospective investigation examined the role of fear of negative evaluation and the personality trait of harm avoidance in the anxiety levels of treated social phobia patients. One hundred and fifty-seven patients with DSM-IV social phobia were assessed before starting treatment and were then followed for up to two years. As expected, greater fear of negative evaluation and higher scores of harm avoidance were associated with greater anxiety at the 6 month follow-up, and harm avoidance remained a significant predictor at 24 months. However, no evidence was found for an interaction between the personality and cognitive variables examined. The findings are discussed in terms of the relative independence of these factors, as well as their potential implications for the treatment of this disorder.  相似文献   
998.
999.
1000.
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