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   2072篇
  免费   140篇
  国内免费   2篇
耳鼻咽喉   16篇
儿科学   72篇
妇产科学   32篇
基础医学   290篇
口腔科学   6篇
临床医学   328篇
内科学   284篇
皮肤病学   19篇
神经病学   381篇
特种医学   50篇
外科学   144篇
综合类   11篇
一般理论   1篇
预防医学   307篇
眼科学   16篇
药学   133篇
肿瘤学   124篇
  2023年   16篇
  2022年   39篇
  2021年   70篇
  2020年   23篇
  2019年   54篇
  2018年   70篇
  2017年   45篇
  2016年   48篇
  2015年   57篇
  2014年   69篇
  2013年   107篇
  2012年   173篇
  2011年   183篇
  2010年   85篇
  2009年   75篇
  2008年   150篇
  2007年   140篇
  2006年   121篇
  2005年   116篇
  2004年   124篇
  2003年   102篇
  2002年   89篇
  2001年   20篇
  2000年   21篇
  1999年   23篇
  1998年   16篇
  1997年   6篇
  1996年   17篇
  1995年   4篇
  1994年   18篇
  1993年   13篇
  1992年   11篇
  1991年   18篇
  1990年   16篇
  1989年   11篇
  1988年   11篇
  1987年   11篇
  1986年   7篇
  1985年   4篇
  1984年   5篇
  1983年   5篇
  1982年   4篇
  1981年   2篇
  1980年   2篇
  1977年   3篇
  1976年   2篇
  1974年   2篇
  1972年   2篇
  1967年   1篇
  1966年   1篇
排序方式: 共有2214条查询结果,搜索用时 15 毫秒
1.
2.
Research on physical activity (PA) by level of acculturation in Hispanic children is limited and findings have been mixed. We examined PA participation by primary language used with parents in a representative sample of 4th, 8th, and 11th grade Texas public school students. Mixed-effects regression models were conducted using cross-sectional data from the 2004–2005 School Physical Activity and Nutrition Study (n = 22,049). Self-reported PA was compared among three language-ethnic groups: Spanish-Hispanic (SH) (referent); English-Hispanic (EH); and English-Other (EO). EH and/or EO girls were generally between 1.25 and 2.58 [OR] times more likely to participate in PA across grade levels, with the largest differences found for school sports in 8th grade girls. EH and EO 8th grade boys were 1.71 (CI: 1.40, 2.10) and 2.06 (CI: 1.68, 2.51) times, respectively, more likely to participate in school sports. Findings indicate important disparities in Spanish-speaking Hispanic children’s PA participation.  相似文献   
3.
4.
5.
Poverty influences health status, life expectancy, health behaviours, and use of health services. This study examined factors influencing the use of health-related services by people living in poverty. In the first phase, 199 impoverished users of health-related services in 2 large Canadian cities were interviewed by their peers. In the second phase, group interviews with people living in poverty (n = 52) were conducted. Data were analyzed using thematic content analysis. Diverse health-related services were used to meet basic and health needs, to maintain human contact, and to cope with life's challenges. Use of services depended on proximity, affordability, convenience, information, and providers' attitudes and behaviours. Use was impeded by inequities based on income status. To promote the health of people living in poverty, nurses and other health professionals can enhance the accessibility and quality of services, improve their interactions with people living in poverty, provide information about available programs, offer coordinated community-based services, collaborate with other sectors, and advocate for more equitable services and policies.  相似文献   
6.
BACKGROUND: Recently, epidemiological and clinical data have revealed important changes with regard to clinical adenovirus infection, including alterations in antigenic presentation, geographical distribution, and virulence of the virus. METHODS: In an effort to better understand the epidemiology of clinical adenovirus infection in the United States, we adopted a new molecular adenovirus typing technique to study clinical adenovirus isolates collected from 22 medical facilities over a 25-month period during 2004-2006. A hexon gene sequence typing method was used to characterize 2237 clinical adenovirus-positive specimens, comparing their sequences with those of the 51 currently recognized prototype human adenovirus strains. In a blinded comparison, this method performed well and was much faster than the classic serologic typing method. RESULTS: Among civilians, the most prevalent adenovirus types were types 3 (prevalence, 34.6%), 2 (24.3%), 1 (17.7%), and 5 (5.3%). Among military trainees, the most prevalent types were types 4 (prevalence, 92.8%), 3 (2.6%), and 21 (2.4%). CONCLUSIONS: For both populations, we observed a statistically significant increasing trend of adenovirus type 21 detection over time. Among adenovirus isolates recovered from specimens from civilians, 50% were associated with hospitalization, 19.6% with a chronic disease condition, 11% with a bone marrow or solid organ transplantation, 7.4% with intensive care unit stay, and 4.2% with a cancer diagnosis. Multivariable risk factor modeling for adenovirus disease severity found that age <7 years (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.4-7.4), chronic disease (OR, 3.6; 95% CI, 2.6-5.1), recent transplantation (OR, 2.7; 95% CI, 1.3-5.2), and adenovirus type 5 (OR, 2.7; 95% CI, 1.5-4.7) or type 21 infection (OR, 7.6; 95% CI, 2.6-22.3) increased the risk of severe disease.  相似文献   
7.
8.
9.
Applied potential tomography (APT) is a new noninvasive, nonradioactive method of measuring gastric emptying, which generates profiles of emptying of liquids that are similar to those obtained simultaneously by scintigraphy and dye dilution. This study validates the ability of APT to measure emptying of a solid beefburger test meal from the stomach by comparing the results obtained with those obtained simultaneously by scintigraphy. When acid secretion was inhibited, there was a significant correlation between the two methods for the time taken for half the meal to empty from the stomach and the amount of meal emptied at different time intervals. Furthermore, the profiles of gastric emptying obtained by APT resembled those obtained by scintigraphy in most studies. If acid secretion was not inhibited, there was no correlation between values obtained by the two methods.  相似文献   
10.
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