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   75402篇
  免费   2582篇
  国内免费   25篇
  2020年   700篇
  2019年   850篇
  2018年   2329篇
  2017年   2227篇
  2016年   2009篇
  2015年   951篇
  2014年   1128篇
  2013年   6013篇
  2012年   2171篇
  2011年   2865篇
  2010年   2164篇
  2009年   1729篇
  2008年   2470篇
  2007年   2634篇
  2006年   1642篇
  2005年   1479篇
  2004年   1389篇
  2003年   1345篇
  2002年   1325篇
  2001年   2103篇
  2000年   2025篇
  1999年   1542篇
  1998年   715篇
  1996年   779篇
  1995年   761篇
  1994年   752篇
  1993年   716篇
  1992年   1459篇
  1991年   1307篇
  1990年   1339篇
  1989年   1186篇
  1988年   1214篇
  1987年   1178篇
  1986年   1187篇
  1985年   1124篇
  1984年   1022篇
  1983年   894篇
  1982年   688篇
  1979年   1058篇
  1978年   766篇
  1975年   906篇
  1974年   930篇
  1973年   1030篇
  1972年   878篇
  1971年   820篇
  1970年   728篇
  1969年   763篇
  1968年   923篇
  1967年   818篇
  1966年   742篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
Gay marriages (as such) are not as yet allowed anywhere but the demand for them is increasing. Most countries take a liberal attitude towards marriage: few obstacles are put in its way. But objections to gay marriages continue to be raised. These objections are refuted and the case for gay marriage is assessed through the prism of various forms of liberalism. The normative argument for allowing gay marriage is shown to be both strong and consistent with many of the values upheld by the opponents of such unions.  相似文献   
53.
54.
55.
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   
56.
57.
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   
58.
59.
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   
60.
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