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   43435篇
  免费   1844篇
  国内免费   11篇
  2020年   442篇
  2019年   576篇
  2018年   798篇
  2017年   817篇
  2016年   835篇
  2015年   602篇
  2014年   728篇
  2013年   3207篇
  2012年   1309篇
  2011年   1410篇
  2010年   858篇
  2009年   813篇
  2008年   1193篇
  2007年   1155篇
  2006年   1103篇
  2005年   963篇
  2004年   949篇
  2003年   867篇
  2002年   891篇
  2001年   1368篇
  2000年   1272篇
  1999年   952篇
  1998年   492篇
  1996年   405篇
  1992年   743篇
  1991年   746篇
  1990年   718篇
  1989年   718篇
  1988年   721篇
  1987年   667篇
  1986年   671篇
  1985年   739篇
  1984年   607篇
  1983年   558篇
  1982年   474篇
  1981年   435篇
  1979年   669篇
  1978年   469篇
  1977年   412篇
  1976年   449篇
  1975年   563篇
  1974年   643篇
  1973年   695篇
  1972年   544篇
  1971年   511篇
  1970年   484篇
  1969年   528篇
  1968年   651篇
  1967年   544篇
  1966年   549篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
A growing literature has observed a significant reduction in pain sensitivity among hypertensive animals and humans. It is uncertain whether a reduced sensitivity to pain can be observed in nonnotensive individuals who go on to develop high blood pressure. Blood pressure (BP) was reassessed in one hundred fifteen 19-year-old boys initially tested at age 14, when they were also presented with a pain stimulus (mechanical finger pressure). Hierarchical regression analyses indicated that information regarding pain tolerance improved prediction of changes in systolic and diastolic blood pressure beyond that afforded by differences in BP at age 14, parental history of hypertension, and body mass index. These analyses suggest that pain sensitivity may be associated with physiological processes involved in the development of sustained high blood pressure.  相似文献   
52.
53.
Suicides among older adults in the United States and Canada in the last decade have accounted for an increasing share of all suicides. In both countries the use of firearms among older adults has steadily increased. Despite these trends, little is known about the extent to which crisis centers are prepared to prevent elder suicide. A survey of AAS-listed crisis prevention centers examined the training, knowledge, and current practices relevant to elder suicide among personnel in 321 crisis prevention centers in both countries. Results revealed insufficient training, a lack of familiarity with recent suicide trends, and limited outreach to older adults.  相似文献   
54.
The country‐of‐origin effect is a topic central to the field of international marketing. Country of origin has been found to exert a particularly potent effect on consumer evaluation in situations where there is a strong link between a country and a particular product category. The present study provides further insight into how this particular effect can be understood. Drawing on a novel conceptualization of how country image and product categories interact, this study tested the relative evaluative relevance of product category with respect to estimates of brand equity across a variety of product categories. The findings suggest that facets of a country's image that are more closely related to the evaluation situation exert a greater influence on the evaluation of brands. This result encourages scholars as well as practitioners to re‐evaluate which situations might cause the country of origin effect to hold managerial relevance and paves the way for new paths toward a more comprehensive understanding of the effect. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
55.
56.
57.
58.
In Experiment 1, rats were trained on a discrimination between rubber- and sandpaper-covered arms of a maze after one group had been pre-exposed to these intra-maze cues. Pre-exposure facilitated subsequent discrimination learning, unless the discrimination was made easier by adding further discriminative stimuli, when it now significantly retarded learning. In Experiment 2, rats were trained on an extra-maze spatial discrimination, again after one group, but not another, had been pre-exposed to the extra-maze landmarks. Here too, pre-exposure facilitated subsequent discrimination learning, unless the discrimination was made substantially easier by arranging that the two arms between which rats had to choose were always separated by 135°. The results of both experiments can be explained by supposing that perceptual learning depends on the presence of features common to S+ and S-.  相似文献   
59.
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