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   747865篇
  免费   52819篇
  国内免费   2214篇
耳鼻咽喉   9507篇
儿科学   24337篇
妇产科学   18733篇
基础医学   115102篇
口腔科学   20802篇
临床医学   67540篇
内科学   144472篇
皮肤病学   16833篇
神经病学   53339篇
特种医学   27346篇
外国民族医学   80篇
外科学   110113篇
综合类   16887篇
现状与发展   3篇
一般理论   161篇
预防医学   53674篇
眼科学   16873篇
药学   57669篇
  11篇
中国医学   3305篇
肿瘤学   46111篇
  2021年   6992篇
  2019年   6500篇
  2018年   9045篇
  2017年   7063篇
  2016年   7840篇
  2015年   8861篇
  2014年   11963篇
  2013年   17449篇
  2012年   23207篇
  2011年   24249篇
  2010年   14363篇
  2009年   13456篇
  2008年   22294篇
  2007年   23852篇
  2006年   24068篇
  2005年   22478篇
  2004年   21839篇
  2003年   20526篇
  2002年   19906篇
  2001年   37616篇
  2000年   38108篇
  1999年   31515篇
  1998年   8298篇
  1997年   6980篇
  1996年   7297篇
  1995年   6886篇
  1994年   6339篇
  1992年   23588篇
  1991年   23439篇
  1990年   22803篇
  1989年   22582篇
  1988年   20454篇
  1987年   19810篇
  1986年   18838篇
  1985年   17587篇
  1984年   12937篇
  1983年   10931篇
  1982年   6030篇
  1979年   11709篇
  1978年   8246篇
  1977年   6932篇
  1976年   6671篇
  1975年   7346篇
  1974年   8611篇
  1973年   8258篇
  1972年   7762篇
  1971年   7227篇
  1970年   6961篇
  1969年   6397篇
  1968年   5856篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
66.
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   
67.
68.
69.

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   
70.
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