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   705677篇
  免费   49940篇
  国内免费   1304篇
耳鼻咽喉   9169篇
儿科学   23281篇
妇产科学   17614篇
基础医学   110564篇
口腔科学   19960篇
临床医学   63837篇
内科学   134472篇
皮肤病学   16166篇
神经病学   49525篇
特种医学   25762篇
外国民族医学   98篇
外科学   104547篇
综合类   14825篇
现状与发展   2篇
一般理论   160篇
预防医学   51452篇
眼科学   16335篇
药学   54025篇
  3篇
中国医学   2363篇
肿瘤学   42761篇
  2021年   5465篇
  2018年   7896篇
  2017年   6124篇
  2016年   6851篇
  2015年   7576篇
  2014年   10302篇
  2013年   15414篇
  2012年   20554篇
  2011年   21546篇
  2010年   12752篇
  2009年   11963篇
  2008年   20046篇
  2007年   21560篇
  2006年   21953篇
  2005年   20476篇
  2004年   20042篇
  2003年   18985篇
  2002年   18501篇
  2001年   36336篇
  2000年   36906篇
  1999年   30390篇
  1998年   7880篇
  1997年   6670篇
  1996年   6978篇
  1995年   6631篇
  1994年   6097篇
  1993年   5592篇
  1992年   22971篇
  1991年   22926篇
  1990年   22312篇
  1989年   22078篇
  1988年   20035篇
  1987年   19418篇
  1986年   18467篇
  1985年   17307篇
  1984年   12698篇
  1983年   10741篇
  1982年   5923篇
  1979年   11518篇
  1978年   8129篇
  1977年   6832篇
  1976年   6595篇
  1975年   7268篇
  1974年   8499篇
  1973年   8141篇
  1972年   7659篇
  1971年   7129篇
  1970年   6880篇
  1969年   6309篇
  1968年   5782篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
46.
47.
In the United States, renal cell carcinoma (RCC) incidence and the prevalence of obesity, an established risk factor for RCC, have been increasing for several decades. RCC is more common among older individuals. We sought to quantify the contribution of excess adiposity to the rising incidence of RCC among individuals 60 years or older. National Institutes of Health-American Association of Retired Persons Diet and Health Study data (n = 453 859 participants, enrolled in 1995-1996, age at enrollment 50-71 years) were used to estimate multivariable-adjusted hazard ratios (HRs) for RCC across body mass index categories and HRs associated with smoking. Population attributable fractions (PAFs) were calculated using estimated HRs and annual overweight/obesity prevalence from the National Health Interview Survey (1985-2008). PAF estimates were combined with RCC incidence from Surveillance, Epidemiology and End Results-13 to calculate annual percent changes in RCC incidence attributable (and unrelated) to overweight/obesity. We found that between 1995 and 2018, among individuals aged 60 years and older, PAF for overweight/obesity increased from 18% to 29% for all RCCs. In comparison, the PAF for smoking declined from 12% to 9%. RCC incidence increased 1.8% per year (95% confidence interval [CI] 1.5%-2.1%) overall, while RCC incidence attributable to overweight/obesity increased 3.8% per year (95%CI 3.5%-4.2%) and RCC incidence unrelated to overweight/obesity increased 1.2% per year (95% CI 0.9%-1.4%). In conclusion, overweight/obesity appears to have contributed importantly to the rising incidence of RCC in the United States since the mid-1990s. Public health interventions focused on reducing overweight and obesity could help substantially in curbing this trend.  相似文献   
48.
49.
50.

Objective

Successful weight loss interventions for African-Americans adolescents are lacking. Cognitive-behavioral interventions seek to develop weight loss skills (e.g., counting calories, goal setting, managing one's environment). Little is known about how well adolescents implement such skills in their daily lives. Study aims were to (1) examine weight loss skills utilization at midpoint and end of a 6-month cognitive-behavioral/motivational interviewing weight loss sequential multiple assignment randomized trial (SMART), and (2) determine if greater skill utilization predicted weight loss at treatment end and 3 months post-treatment.

Method

One hundred and eighty six African-Americans adolescents with obesity and their caregiver were first randomly assigned to complete 3 months of cognitive-behavioral and motivational interviewing family-based weight loss treatment in their home or in the research office (Phase 1). Nonresponders (i.e., those who lost < 3% of initial weight, n?=?161) were rerandomized to 3 months of continued skills training (n?=?83) or contingency management (n?=?78) for Phase 2; responders were allocated to 3 months of relapse prevention (n?=?20). Adolescents’ frequency of weight loss skills utilization was assessed via questionnaire at treatment midpoint and end.

Results

Higher treatment attendance was associated with better skill utilization. Higher skill utilization was associated with more weight loss at treatment end, whereas higher baseline confidence was associated with more weight loss at follow-up.

Conclusions

This study indicates the importance of attending weight loss intervention sessions to develop and strengthen weight loss skills in African-American adolescents with obesity, and strengthening confidence to use such skills for continued weight loss.  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