首页 | 官方网站   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   18519篇
  免费   1156篇
  国内免费   49篇
医药卫生   19724篇
  2023年   138篇
  2022年   91篇
  2021年   572篇
  2020年   362篇
  2019年   521篇
  2018年   637篇
  2017年   402篇
  2016年   419篇
  2015年   557篇
  2014年   668篇
  2013年   897篇
  2012年   1445篇
  2011年   1551篇
  2010年   829篇
  2009年   789篇
  2008年   1351篇
  2007年   1377篇
  2006年   1325篇
  2005年   1179篇
  2004年   1007篇
  2003年   982篇
  2002年   907篇
  2001年   138篇
  2000年   102篇
  1999年   132篇
  1998年   118篇
  1997年   96篇
  1996年   89篇
  1995年   101篇
  1994年   100篇
  1993年   80篇
  1992年   50篇
  1991年   55篇
  1990年   41篇
  1989年   38篇
  1988年   33篇
  1987年   38篇
  1986年   29篇
  1985年   31篇
  1984年   47篇
  1983年   34篇
  1982年   37篇
  1981年   50篇
  1980年   22篇
  1979年   25篇
  1978年   32篇
  1977年   26篇
  1976年   28篇
  1973年   20篇
  1969年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Incidence of human papillomavirus (HPV) attributable oropharyngeal cancers (OPCs) has been increasing globally, especially among men in high-income countries. There is a lack of studies comparing oral HPV prevalence by age and country among healthy men. The purpose of our study was to assess oral HPV prevalence by country and age. Participants of the HPV Infection in Men Study (HIM), a cohort of 3,098 healthy men from São Paulo, Brazil, Cuernavaca, Mexico and Tampa, USA, were studied. Oral HPV prevalence and type distribution were assessed using the SPF10 PCR-DEIA-LiPA25 system. The prevalence of any HPV in Brazil, Mexico and the US was 8.7% (95% CI: 7.1%, 10.4%), 10.0% (95% CI: 8.3%, 12.1%) and 7.6% (95% CI: 5.9%, 9.5%), respectively, while the prevalence of high-risk HPV was 5.3% (95% CI: 4.1%, 6.7%), 7.3% (95% CI: 5.7%, 9.0%) and 5.4% (95% CI: 4.0%, 7.0%), respectively. No significant differences in prevalence of grouped HPV types were observed by country despite significant differences in sexual behaviors. However, the age-specific prevalence of oral HPV differed by country. Brazilian (6.0% [95% CI: 3.4%, 9.7%]) and Mexican (9.2% [95% CI: 5.6%, 14.0%]) participants had peak high-risk HPV prevalence among men aged 41–50 years whereas the US participants had peak prevalence at ages 31–40 years (11.0% [95% CI: 6.4%, 17.3%]). In conclusion, oral HPV prevalence was low with no difference in overall prevalence observed by country. Factors associated with the differences in oral HPV age-patterning by country and sexual orientation require further study.  相似文献   
5.

Objectives

To evaluate the association between urinary incontinence and disordered eating, in elite female athletes.

Design

This cross-sectional study included 744 young and healthy Portuguese women: 372 elite athletes and 372 age-matched non-athletes, mean age 21 ± 5.3 years.

Methods

Data regarding clinical, demographic, and sport practice characteristics were collected by questionnaire. The International Consultation on Incontinence Questionnaire-Urinary Incontinence-Short Form was applied to identify urinary incontinence. The Eating Disorder Examination Questionnaire was applied to identify disordered eating. Odds ratios with 95% confidence intervals (95% CI) were used to estimate the association between UI and disordered eating.

Results

The prevalence of urinary incontinence in athletes and non-athletes was 29.3% and 13.4%, p < 0.001, respectively. No difference in prevalence of disordered eating was found between athletes (17.7%) and non-athletes (20.2%), p = 0.435. Urinary incontinence was associated with disordered eating only in the athletes. After adjustment for age, type of sport, smoking and alcohol intake, athletes with disordered eating presented increased odds of urinary incontinence of any type over athletes without disordered eating (OR = 3.09; 95% CI: 1.74–5.50).

Conclusions

Athletes with disordered eating were three times more likely to present urinary incontinence than women without disordered eating. There is a need for further studies to elaborate on mechanisms for this association.  相似文献   
6.
7.
Porcine epidemic diarrhoea virus (PEDV) infects pigs of all ages causing vomiting and diarrhoea. PEDV is transmitted via the oral–faecal route, and a very low dose is enough to infect susceptible pigs, resulting in significant production losses. This short communication aims to describe the introduction of PEDV into a 10,000-sow farrow-to-wean farm located in northwest Mexico. Following the onset of clinical signs, an outbreak investigation was conducted to determine the most probable route of introduction. Based on data collected from interviews, construction of a timeline of events, and the detection of PEDV RNA in feed samples and samples collected from various surfaces of feed transport vehicles, it was concluded that the most probable route for PEDV incursion into this breeding herd was contaminated feed or a contaminated feed transport vehicle. This paper describes how feed or feed transport could serve as potential routes of PEDV infection to a farm and highlights the importance of establishing biosecurity programs to mitigate these risks.  相似文献   
8.
9.
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-23

京公网安备 11010802026262号