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   173788篇
  免费   7918篇
  国内免费   157篇
  181863篇
  2020年   2770篇
  2019年   3431篇
  2018年   3505篇
  2017年   3932篇
  2016年   4592篇
  2015年   3904篇
  2014年   4788篇
  2013年   23379篇
  2012年   4468篇
  2011年   3532篇
  2010年   3846篇
  2009年   4733篇
  2008年   3823篇
  2007年   3324篇
  2006年   3914篇
  2005年   3904篇
  2004年   3419篇
  2003年   3068篇
  2002年   2859篇
  2001年   3457篇
  2000年   3296篇
  1999年   3246篇
  1998年   2816篇
  1997年   2668篇
  1996年   2598篇
  1995年   2420篇
  1994年   2392篇
  1993年   2336篇
  1992年   2699篇
  1991年   2539篇
  1990年   2396篇
  1989年   2295篇
  1988年   2266篇
  1987年   2262篇
  1986年   2280篇
  1985年   2475篇
  1984年   2570篇
  1983年   2344篇
  1982年   2370篇
  1981年   2353篇
  1980年   2196篇
  1979年   2260篇
  1978年   2192篇
  1977年   2162篇
  1976年   1976篇
  1975年   2064篇
  1974年   2121篇
  1973年   2016篇
  1972年   1619篇
  1971年   1546篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
951.
Free-recall and multiple-choice measures of memory for landmarks, sequential order, turns, and route configurations were obtained from younger and older adults after they viewed slides of 2 overlapping routes. Instructions focused attention on either the contents of the slides or on the course of the path; a control condition provided no orientational instructions. Half the subjects viewed maplike diagrams of the joint spatial configuration. Age interacted with instruction only for multiple-choice tests of landmark memory. Age interacted with diagram for each of the other 3 route memory components, although the generality of this interaction across instruction condition depended on whether free-recall or multiple-choice tests were used. The results suggest that route memory may involve both scene and layout representation, which may be differentially sensitive to age and presentational variables.  相似文献   
952.
This study examined whether chronic physical exercise activity is associated with better neurocognitive performance in older adults. One hundred five men participated in 1 of 3 age groups (18-28, 35-45, and 60-73). For each age group, subjects were classified as high or low in fitness on the basis of self-reported activity levels and the results of a submaximal bicycle ergometer test. A comprehensive battery of neuropsychological tests was administered to each subject, and older subjects scored significantly lower than the younger groups on most tests. Significant differences between high- and low-fit subjects were found only on tasks with heavy visuospatial demands, and these differences were most notable in the older adult group. These findings suggest that participation in aerobic exercise activity selectively preserves some cognitive functions that normally decline with age. The benefits of activity appear to be most evident on tasks that require visuospatial processing.  相似文献   
953.
Older adults' life satisfaction can be better understood in light of their personal goals. This study of 179 elders examined (a) how goals correlate with satisfaction, (b) whether elders maintain satisfaction by accommodating goals to past losses, and (c) how correlations between satisfaction and key predictors differ among groups with different goals. Satisfaction was related positively to social maintenance and energetic life-style goals and negatively to concerns for improvement, disengagement, stability, and reduced activity. Past losses were correlated with current goals but not with satisfaction, consistent with the notion of accommodation. A cluster analysis identified 5 patterns of goals: high demand, age prescribed, self-focused, socially engaged, and low demand. Correlations between satisfaction and other predictors differed by cluster, suggesting that the determinants of elders' satisfaction depend on personal goals.  相似文献   
954.
Subjects performed a serial reaction time task (adopted from Nissen & Bullemer, 1987) that contained a repeating pattern of spatial locations. In Experiment 1, following 20 repetitions of a 10- or 16-element pattern, reaction time was equally disrupted for both younger and older people when the sequence became random. In Experiment 2, the response times for subjects encountering the 10-element pattern were compared with those of subjects encountering a random sequence. These response time functions diverged at the same point in training for the 2 age groups. Thus, on this indirect measure of response time facilitation, both experiments revealed age similarity in the rate of pattern learning. In contrast, on a subsequent direct test of pattern learning that required prediction, the younger people earned a higher percentage correct score than the older in both experiments. Age-related dissociations between direct and indirect measures of learning and comparisons with memory-impaired populations are discussed.  相似文献   
955.
956.
Short-term memory for actions was investigated for young adult and elderly adult subjects with the Brown-Peterson procedure at retention intervals of 0 and 15 s. The short-term memory trials were followed by the long-term recall of the prior to-be-remembered actions. The 15-s retention interval was filled either with no activity or with 1 of 3 different interfering activities. Verbal interference had little effect on short-term memory at either age level. Actions performed in the interval either by the subjects or by the experimenter produced significantly lower recall scores at each age level, with the decrement being more pronounced for the elderly than for the young subjects. The long-term memory results indicated that successful short-term recall enhanced later long-term recall, regardless of age level.  相似文献   
957.
The dimensions by which adults of differing ages experience emotion were studied by self-administering questionnaires administered to older adults (n = 828) recruited from Elderhostel programs, middle-aged (ages 30-59) children of Elderhostel attenders (n = 231), and young adult (ages 18-29) subjects recruited from college classes or through Elderhostel participants (n = 207). Elders were higher in emotional control, mood stability, and emotional maturity through moderation and leveling of positive affect and lower in surgency, psychophysiological responsiveness, and sensation seeking. These findings are consistent with the hypothesized increase in self-regulatory capacity with age. These cross-sectional differences cannot, however, be distinguished from cohort-related explanations; they require considerable replication across different types of subjects and further characterization of the dimensions in terms of their functions for self-regulation.  相似文献   
958.
Researchers examined the importance of similar ethnicity and the preference for a counselor of the same sex among American Indian secondary school students.  相似文献   
959.
Helms (1984) presented a model to explain the influence of Black and White racial identity development on counseling interactions. The purpose of this study was to examine her hypothesis that specific combinations of racial identity attitudes contribute to qualitatively different counseling process and outcome or relationship types.  相似文献   
960.
The present study determined if it was possible to develop a selection procedure which would effectively select machine operator applicants. A concurrent validity study was conducted on 140 employees with a job simulation as the criterion. The results indicated a correlation with the criterion of .71, and the Lawshe (1983) test of fairness revealed no significant bias for minority or female applicants. The utility analysis indicated a 16% increase in output would occur with the use of the validated selection system.  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