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   3424129篇
  免费   244511篇
  国内免费   10836篇
医药卫生   3679476篇
  2019年   27768篇
  2018年   38989篇
  2017年   29741篇
  2016年   33973篇
  2015年   38368篇
  2014年   52915篇
  2013年   80644篇
  2012年   107804篇
  2011年   114130篇
  2010年   68413篇
  2009年   64808篇
  2008年   105992篇
  2007年   112284篇
  2006年   113908篇
  2005年   109373篇
  2004年   104898篇
  2003年   101154篇
  2002年   97784篇
  2001年   159336篇
  2000年   163533篇
  1999年   138066篇
  1998年   40335篇
  1997年   35807篇
  1996年   35814篇
  1995年   34570篇
  1994年   31902篇
  1993年   30008篇
  1992年   108450篇
  1991年   104839篇
  1990年   101662篇
  1989年   97838篇
  1988年   89860篇
  1987年   88139篇
  1986年   83111篇
  1985年   79433篇
  1984年   59394篇
  1983年   50700篇
  1982年   30216篇
  1981年   26955篇
  1979年   53037篇
  1978年   37676篇
  1977年   31600篇
  1976年   29835篇
  1975年   31418篇
  1974年   37485篇
  1973年   35894篇
  1972年   33530篇
  1971年   31203篇
  1970年   28889篇
  1969年   27345篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
Potential for widespread transmission of HIV/AIDS among American Indian (AI) adolescents exists, yet no evidence-based interventions (EBIs) have been adapted and evaluated with this population. Intensive psychoeducation may improve knowledge and decision-making which could potentially translate to reductions in HIV risk behaviors. A peer group randomized controlled comparison of an adapted EBI vs. control was delivered over an eight-day summer basketball camp in one reservation-based tribal community to adolescents ages 13–19. Outcome data were gathered immediately post-camp and at 6 and 12 months follow-up. Self-selected peer groups were randomized to intervention (n = 138) or control (n = 129) conditions for a total sample of 267 participants (56.2% female), mean age 15.1 years (SD = 1.7). Intervention participants had better condom use self-efficacy post-camp (Adjusted Mean Difference [AMD] = ?0.75, p < 0.005) and at 6 (AMD = ?0.44, p < 0.005) and 12 months (AMD = ?0.23, p < 0.05) follow-up. Intervention participants also had higher HIV prevention and transmission knowledge (post-camp: AMD = 0.07, p < 0.01; 6 months: AMD = 0.06, p < 0.01) were more likely to believe condoms prevent sexually transmitted infections (post-camp: RR = 1.41, p < 0.005; 6 months: RR = 1.34, p < 0.05), to talk with an adult about HIV/AIDS (post-camp: RR=1.78, p < 0.005; 6 months: RR = 1.14, p < 0.005), had higher partner negotiation efficacy related to substance use during sex (post-camp: AMD = 0.37, p < 0.01), and were more likely to intend to use a condom (post-camp: RR = 1.39, p < 0.01). The adapted intervention had short- and medium-term impacts on AI adolescent risk for HIV/AIDS, but attenuated at 12 months. Intervention delivery through a community-based camp is feasible and acceptable with strong retention. Additional study is needed to evaluate the adapted intervention's impact on sexual risk behaviors and if booster sessions and parent involvement translate to long-term impacts.  相似文献   
10.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  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-23

京公网安备 11010802026262号