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   59042篇
  免费   1615篇
  国内免费   16篇
  2020年   482篇
  2019年   624篇
  2018年   4088篇
  2017年   3500篇
  2016年   3007篇
  2015年   821篇
  2014年   846篇
  2013年   3284篇
  2012年   1954篇
  2011年   3668篇
  2010年   3249篇
  2009年   2275篇
  2008年   2873篇
  2007年   3350篇
  2006年   1145篇
  2005年   1203篇
  2004年   1108篇
  2003年   1002篇
  2002年   959篇
  2001年   1218篇
  2000年   1192篇
  1999年   900篇
  1998年   431篇
  1997年   417篇
  1996年   372篇
  1995年   374篇
  1994年   355篇
  1993年   357篇
  1992年   740篇
  1991年   648篇
  1990年   708篇
  1989年   607篇
  1988年   640篇
  1987年   599篇
  1986年   605篇
  1985年   544篇
  1984年   505篇
  1983年   484篇
  1979年   569篇
  1978年   397篇
  1975年   449篇
  1974年   493篇
  1973年   527篇
  1972年   394篇
  1971年   387篇
  1970年   348篇
  1969年   400篇
  1968年   469篇
  1967年   426篇
  1966年   350篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
31.
32.
33.
OBJECTIVE: Compare the efficacy of a multicomponent social support intervention to standard-of-care counseling on medication adherence among HIV-infected patients initiating antiretroviral therapy. DESIGN: Randomized controlled trial. Generalized estimating equations tested for differences in the percentage of participants achieving 90% adherence. MAIN OUTCOME MEASURES: Pill-taking, electronically monitored over 6 consecutive months; plasma viral load (VL), assessed at 3 and 6 months following initiation of therapy. RESULTS: Of 226 participants who were randomized and began the trial, 87 (38%) were lost to the study by 6 months. The proportion of adherent participants declined steadily over time, with no time by group interaction. Sustained adherence was associated with increased odds of achieving an undetectable VL (OR=1.78; 95% CI=1.01, 3.13). In intention-to-treat analyses, a larger proportion of the intervention group than the control group was adherent (40.15% vs. 27.59%, p=.02) and achieved an undetectable VL p=.04). However, the majority of participants who remained on study experienced some reduction in VL (>or=1-log drop or undetectable), regardless of experimental condition. CONCLUSION: The multicomponent social support intervention significantly improved medication adherence over standard-of-care counseling; evidence for improved virologic outcomes was inconsistent. Early discontinuation of care and treatment may be a greater threat to the health of HIV patients than imperfect medication-taking.  相似文献   
34.
The authors used recursive partitioning methods to identify combinations of baseline characteristics that predict 2-year physical activity success in each of 3 physical activity interventions delivered in the multisite Activity Counseling Trial. The sample consisted of 874 initially sedentary primary care patients, ages 35-75 years, who were at risk for cardiovascular disease. Predictors of 2-year success were specific to each intervention and represented a range of domains, including physiological, demographic, psychosocial, health-related, and environmental variables. The results indicate how specific patient subgroups (e.g., obese, unfit individuals; high-income individuals in stable health) may respond differently to varying levels and amounts of professional assistance and support. The methods used provide a practical first step toward identifying clinically meaningful patient subgroups for further systematic investigation.  相似文献   
35.
This study evaluated cardiovascular responses (CVR) to an active speech task with blatantly discriminatory (BRC) versus neutral (NRC) stimuli and an anger recall task in a sample of Black men (N = 73; age 18 to 47). Diastolic blood pressure scores were higher for NRC versus BRC stimuli during anger recall (p = .05). Moreover, persons in the NRC group who perceived high levels of racism (vs. no racism or BRC group) during active speech showed larger increases in blood pressure across postspeech rest, anger recall, and subsequent rest (p = .03). The notable elevation in CVR in response to an ambiguous event extends current models of racism suggesting that subtle racism is a psychosocial stressor that erodes health through chronically elevated CVR.  相似文献   
36.
37.
38.
39.
40.
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