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   25690篇
  免费   932篇
  国内免费   11篇
  2018年   354篇
  2017年   368篇
  2016年   384篇
  2015年   283篇
  2014年   358篇
  2013年   1874篇
  2012年   622篇
  2011年   665篇
  2010年   455篇
  2009年   423篇
  2008年   664篇
  2007年   585篇
  2006年   561篇
  2005年   477篇
  2004年   491篇
  2003年   493篇
  2002年   504篇
  2001年   645篇
  2000年   653篇
  1999年   514篇
  1998年   269篇
  1997年   292篇
  1996年   285篇
  1995年   263篇
  1992年   503篇
  1991年   464篇
  1990年   454篇
  1989年   424篇
  1988年   446篇
  1987年   416篇
  1986年   455篇
  1985年   442篇
  1984年   386篇
  1983年   342篇
  1982年   258篇
  1981年   272篇
  1979年   416篇
  1978年   336篇
  1977年   294篇
  1976年   314篇
  1975年   354篇
  1974年   437篇
  1973年   472篇
  1972年   352篇
  1971年   371篇
  1970年   343篇
  1969年   366篇
  1968年   437篇
  1967年   404篇
  1966年   420篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
261.
Age differences in memory performance were studied in a probability sample of a cross-section of 1,491 adults living in the Detroit metropolitan area, with an oversample of those age 60 and older. Both a recall and a recognition measure were adapted to the survey context by querying respondents about the nature of the questions asked in an immediately preceding interview. Subjective memory assessment was also measured, using global memory ratings performed by the respondent, his or her spouse, and the interviewer. A clear, age-related decline in memory performance was found in this population sample. Subjective memory assessment also declined across age groups, but the relation was weaker. On the basis of multiple regression analyses of the recognition measure and the respondent's self-rated memory, which were judged to have the best measurement qualities, a substantial part of these age differences can be accounted for by differences in sociodemographic composition between age groups, by cognitive functioning and physical health.  相似文献   
262.
Relationship of severity of dementia to caregiving stressors   总被引:4,自引:0,他引:4  
In studies of individual differences and longitudinal changes in stress and coping among dementia caregivers, assessing severity of patient impairment is critically important. It is proposed that with the progression of dementia, cognitive impairment may steadily increase, but other stressful behavioral symptoms peak at various stages of dementia. Cross-sectional data from 49 caregiving families and longitudinal follow-up data from 48 families suggest that instrumental self-care deficits begin early in dementia, and basic self-care deficits increase with dementia severity, but that many distressing behavioral symptoms decrease in late dementia. Assessments of dementia patient severity should be multidimensional, and increases and decreases in various dementia patient stressors over time should be considered as factors influencing caregiver coping.  相似文献   
263.
Models of event causation and affective processes were used to design an experimental intervention for older adults. Ss were 2 at-risk populations, recently disabled and recently bereaved, each with matched nonrisk controls. Ss were randomly assigned to a placebo-contact group, a no-contact control group, or a 4-session, 10-week intervention focused on enhancing perceived control. Dependent variables assessed were personal mastery, psychological well-being and distress, positive and negative affect, and measures of daily events and activities. The intervention was nested within a 16-month longitudinal assessment of stress and adaptation processes in a large sample of community residents. The intervention had mixed effects on reports of personal mastery, but it significantly increased engagement in desirable activities and significantly decreased psychological distress and negative affect. Effects tended to be short-lived, however. Effects of the intervention tended to be particularly significant for the disabled group.  相似文献   
264.
Deficits in semantic encoding have been described in patients with frontal lobe disease who also show memory impairments. As a group, patients with multiple sclerosis (MS) exhibit memory impairment, fail to make effective use of semantic encoding to aid memory, and perform poorly on verbal fluency and concept formation tests which are sensitive to frontal lobe damage. In the present study the semantic encoding capacity of MS patients was measured using a modification of Wicken's release from proactive interference (PI) paradigm. Individual patients varied considerably in the severity of their impairments on verbal fluency, verbal recognition memory and on Wisconsin Card Sorting Task, but even patients who evidenced both memory impairment and signs of frontal lobe dysfunction showed normal release from PI after a categorical shift. Memory disturbances in MS are unlikely to result from an incapacity for semantic encoding, which seems preserved in MS, but may arise instead from deficits in processing information rapidly.  相似文献   
265.
We studied central-place foraging in rats (Rattus norvegicus) by placing food items that varied in size and weight at the ends of a 4-arm radial maze. In Experiments 1-3, rats increasingly tended to carry food to the center of the maze as the size of those items increased. Very large food items often were hoarded in the center. Rats consumed food faster on the arms than in the center, and rats traveled faster when carrying food than when not. Blocking arm entrances increased travel time between the center and the arms and decreased food carrying at every item weight except the largest. In Experiments 4-6, important conditions that influence the degree of food-carrying behavior were discovered; these were the intersection of maze arms, the presence of a conspecific, and the use of open vs. closed maze arms.  相似文献   
266.
This paper addresses the use of the weekly written summary with patients in group psychotherapy. In an effort to stimulate group process and effect cotherapist communication, the authors instituted this group recording in an ongoing psychodynamically oriented mixed adult group. While the utilization of this device did, in fact, stimulate the group process and became an important part of the group's life, the therapists additionally saw significant effects upon their working alliance. These included increased focused dialogue upon group dynamics, more purposeful planning for group interventions, and heightened awareness of the significance of interventions in the group.Ms. Bosman-Clark is formerly Clinical Instructor, Department of Psychiatry, Baylor College of Medicine.  相似文献   
267.
A combined multi-attribute utility and expectancy-value model has repeatedly been found to yield a worse fit to choices than to preference ratings. The present study investigated two possible explanations for this finding. First, people's belief-value structures may change in the choice task as they try to find the best alternative. Second, a difficult choice task may cause the decision maker to use simplifying heuristics. In the first of two experiments, subjective belief-value structures were measured on two occasions separated by about one week. Immediately before the second measurement, different groups of subjects performed a choice task, gave preference ratings, or performed a control task. The results did not support an interpretation of the greater difficulty of predicting choices in terms of changes in belief-value structures. However, the notion of simplifying heuristics received support by the finding that adopting simpler versions of the original model improved the predictions of the choices. In the second experiment, beliefs were measured immediately before or after each of a series of choices or preference ratings. The results indicated that although temporary changes in beliefs may occur, they can hardly provide a full account of the differential predictability of preferences and choices.  相似文献   
268.
269.
Perceptual speed in adulthood: cross-sectional and longitudinal studies   总被引:3,自引:0,他引:3  
Cross-sectional data on age differences in perceptual speed are presented from the Seattle Longitudinal Study for the age range 22-91 years (N = 1,620, first assessed in 1977; N = 628, first assessed in 1984). In addition, 838 subjects were followed over the 7-year interval. Markers of perceptual speed were the Identical Pictures and Finding A's tests from the ETS Kit of Factor-Referenced Tests. Significant age differences, age changes, and cohort differences were found at both observed variable and latent construct levels. Cross-lagged correlations examine the role of perceptual speed in predicting later performance on other abilities (Verbal Meaning, Inductive Reasoning, Spatial Orientation, Number, and Word Fluency). When perceptual speed is partialled out of scores for these abilities, aging effects are reduced markedly for all abilities, but least for Spatial Orientation and Inductive Reasoning.  相似文献   
270.
Recent work has questioned whether a single job evaluation instrument can reliably measure jobs from different job families. To test this, a generalizability study was done to determine the reliability of three job evaluation instruments: one for male-dominated jobs, MIMA-Shop, one for female-dominated jobs, MIMA-office and one which evaluated both types, FES. Initial results indicated that the latter instrument suffered no loss in reliability, and that all three instruments were equally highly reliable. A second analysis evaluated the reliability of the FES for male-dominated jobs separately from the reliability of the FES for female-dominated jobs. These results indicated no significant difference in reliability for male-dominated jobs and for female-dominated jobs. Implications of these findings were discussed.A previous version of this paper was presented at the 95th Annual Convention of the American Psychological Association at New York City, August 1987.  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