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   36210篇
  免费   2702篇
  国内免费   102篇
耳鼻咽喉   414篇
儿科学   916篇
妇产科学   495篇
基础医学   4614篇
口腔科学   715篇
临床医学   3401篇
内科学   7709篇
皮肤病学   514篇
神经病学   3966篇
特种医学   1674篇
外国民族医学   3篇
外科学   5337篇
综合类   721篇
一般理论   89篇
预防医学   3197篇
眼科学   683篇
药学   2208篇
中国医学   49篇
肿瘤学   2309篇
  2023年   119篇
  2022年   183篇
  2021年   508篇
  2020年   284篇
  2019年   497篇
  2018年   631篇
  2017年   471篇
  2016年   535篇
  2015年   614篇
  2014年   925篇
  2013年   1457篇
  2012年   2230篇
  2011年   2356篇
  2010年   1278篇
  2009年   1234篇
  2008年   2249篇
  2007年   2458篇
  2006年   2411篇
  2005年   2606篇
  2004年   2281篇
  2003年   2101篇
  2002年   2114篇
  2001年   483篇
  2000年   444篇
  1999年   491篇
  1998年   484篇
  1997年   457篇
  1996年   438篇
  1995年   400篇
  1994年   330篇
  1993年   315篇
  1992年   375篇
  1991年   378篇
  1990年   345篇
  1989年   297篇
  1988年   270篇
  1987年   288篇
  1986年   273篇
  1985年   278篇
  1984年   289篇
  1983年   271篇
  1982年   309篇
  1981年   311篇
  1980年   253篇
  1979年   174篇
  1978年   175篇
  1977年   118篇
  1976年   140篇
  1975年   105篇
  1974年   127篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
The 2008 dioxin crisis occurred as a result of contamination of Irish pork. The event had significant implications for Ireland’s economy and the reputation of its agricultural industry, as well as raising concerns for human health. This study describes the results of a content analysis of Irish and UK newspaper coverage of the 2008 Irish dioxin crisis, as this is likely to provide insight into how public perceptions of this issue were shaped. Articles from 16 print publications were systematically sampled for the period December 2008 to February 2009. The resulting data set of 141 articles was examined using a coding protocol developed based on previous research and refined during piloting. Results indicated that the dioxin crisis was primarily portrayed by the media as an industry/economic crisis, dominant in 26.9% of articles in the sample. Within this dominant portrayal, the agricultural industry was frequently cited as being in crisis (42.6%); however, the implications of the crisis on the wider economic environment also received attention (17.7%). Differences between Irish and UK-based media were also examined, revealing that while the Irish media most frequently described the crisis in terms of its impact on the industry and economy, the UK media were more likely to portray the crisis as a risk to health. These dominant media messages and message framings have implications for the public understanding of the issue in each country and potential consequences regarding perception of the adequacy of existing food policy and regulatory oversight.  相似文献   
3.
4.
5.
6.
7.
8.

Background  

There are no published utilities for the post-anesthesia state obtained by the standard gamble method (SG).  相似文献   
9.
10.
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   
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