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   41519篇
  免费   1546篇
  国内免费   11篇
  43076篇
  2019年   444篇
  2018年   646篇
  2017年   606篇
  2016年   692篇
  2015年   508篇
  2014年   602篇
  2013年   3893篇
  2012年   1053篇
  2011年   1100篇
  2010年   704篇
  2009年   667篇
  2008年   995篇
  2007年   890篇
  2006年   841篇
  2005年   704篇
  2004年   682篇
  2003年   713篇
  2002年   695篇
  2001年   1327篇
  2000年   1289篇
  1999年   994篇
  1996年   533篇
  1995年   495篇
  1994年   488篇
  1993年   479篇
  1992年   978篇
  1991年   895篇
  1990年   897篇
  1989年   778篇
  1988年   777篇
  1987年   775篇
  1986年   772篇
  1985年   767篇
  1984年   673篇
  1983年   556篇
  1982年   435篇
  1981年   458篇
  1979年   653篇
  1978年   472篇
  1976年   436篇
  1975年   590篇
  1974年   605篇
  1973年   659篇
  1972年   625篇
  1971年   559篇
  1970年   503篇
  1969年   495篇
  1968年   597篇
  1967年   531篇
  1966年   489篇
排序方式: 共有10000条查询结果,搜索用时 6 毫秒
11.
12.
13.
Since 1970 about 80% of the research on oral communication apprehension has used one of two versions of McCroskey's Personal Report of Communication Apprehension. The original 20-item PRCA was introduced for the purpose of measuring apprehension beyond the traditional public speaking context. Although the PRCA-20 is reliable, some serious criticism of it has centered on its ability to tap interpersonal behavior outcomes. In an attempt to bolster its interpersonal applicability, five “interpersonally-oriented” items were added to form the PRCA-25. The studies reported herein demonstrate that both versions fail to possess sufficient reliable variance to be applicable to contexts other than public settings. In addition, it was found that the interpersonal items are a separate component of the PRCA, and as such, do not justify being treated equal in terms of additivity and, therefore, reduce the construct integrity of the PRCA.  相似文献   
14.
15.
In two experiments, hungry rats were given instrumental lever-press training for an appetitive reinforcer and, in addition, were exposed to another type of food which was not contingent on lever pressing. In the first experiment, exposure to each type of food was on separate days, whereas in the second experiment rats were exposed to each type of food in strict alternation within each session. Subsequently, a food aversion was conditioned to the reinforcer for the experimental group and to the non-contingent food for the control group. In both experiments, animals with an aversion to the reinforcer responded less in an extinction test than animals with an aversion to the non-contingent food. Subsequent reacquisition tests confirmed that the aversion to the non-contingent food in the control group was of comparable strength with that to the reinforcer in the experimental group. The results were discussed in terms of whether the reinforcer is encoded in the associative structure set up by exposure to an instrumental contingency.  相似文献   
16.
17.
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   
18.
19.
20.
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