全文获取类型
收费全文 | 42365篇 |
免费 | 1663篇 |
国内免费 | 17篇 |
出版年
2020年 | 421篇 |
2019年 | 465篇 |
2018年 | 682篇 |
2017年 | 698篇 |
2016年 | 733篇 |
2015年 | 547篇 |
2014年 | 705篇 |
2013年 | 3240篇 |
2012年 | 1224篇 |
2011年 | 1220篇 |
2010年 | 813篇 |
2009年 | 772篇 |
2008年 | 1111篇 |
2007年 | 1109篇 |
2006年 | 1013篇 |
2005年 | 895篇 |
2004年 | 878篇 |
2003年 | 819篇 |
2002年 | 844篇 |
2001年 | 1286篇 |
2000年 | 1276篇 |
1999年 | 975篇 |
1998年 | 463篇 |
1997年 | 461篇 |
1996年 | 448篇 |
1992年 | 833篇 |
1991年 | 776篇 |
1990年 | 784篇 |
1989年 | 698篇 |
1988年 | 712篇 |
1987年 | 677篇 |
1986年 | 706篇 |
1985年 | 694篇 |
1984年 | 625篇 |
1983年 | 550篇 |
1982年 | 420篇 |
1979年 | 617篇 |
1978年 | 517篇 |
1977年 | 437篇 |
1976年 | 442篇 |
1975年 | 551篇 |
1974年 | 667篇 |
1973年 | 690篇 |
1972年 | 519篇 |
1971年 | 526篇 |
1970年 | 475篇 |
1969年 | 529篇 |
1968年 | 635篇 |
1967年 | 579篇 |
1966年 | 561篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
201.
Age differences in short-term retroactive interference, unconfounded with age differences in rehearsal in the retention interval of the Brown-Peterson Task, were not found in a cross-sectional study of adults 18-32 and 64-78 years of age. Degree of retroactive interference was manipulated conjointly with distractor interval length (0-15 s). Individual memory span was assessed and used as the list length in order to achieve stimulus equivalence of memory loads across individuals and age groups. An attention-demanding matching task that adjusted itself in difficulty to the individual's attentional capacity was used as the distractor activity. Covert rehearsal during the retention interval was inferred using several measures, including a comparison of distractor task performance in the presence and in the absence of a memory load, and rehearsers were excluded from the primary analyses. We conclude that there is no interference proneness with increasing age in the present study. 相似文献
202.
Surviving members of the Berkeley Older Generation Study were interviewed and tested with the Wechsler Adult Intelligence Scale in 1969-1970 and again in 1983-1984, when subjects' ages ranged from 73 to 93. Health was assessed by self-reports at both measurement periods. Although many individuals showed some decline in intellectual functioning, substantial individual differences were apparent at all age levels. More than one half of the subjects showed no reliable change, and a minority showed a reliable increase in verbal scores. The role of self-reported health has increasing importance in the maintenance of intellectual functioning in advanced old age. 相似文献
203.
We investigated longitudinally the effects of a stroke on the social support systems and well-being of the patient's primary support person, both acutely and as the condition stabilized. Individuals who had suffered a first stroke and a primary support person participated in two waves of data collection, carried out in 6-month intervals beginning 7 weeks after the stroke. Our data show that the prevalence of depressive symptoms is from 2 1/2 to 3 1/2 times higher than rates found among representative samples of middle-aged and elderly populations. Mean level of depression did not change over time, although level of optimism declined significantly. Multiple regression analyses showed that levels of depression and perceived burden in support persons are highly related to aspects of the stroke such as its severity, and that demographic variables such as age and income play a relatively minor role in attenuating these relations in the acute adjustment phase. However, from 7 to 9 months after the stroke, well-established demographic variables such as health, income, and age were significant predictors of depression. Individuals who were older and who had good health and higher incomes were least depressed. 相似文献
204.
Young and older adults were presented with pictures for study. Their recognition of the information was tested at five retention intervals: immediately, and 48 hr, 1 week, 2 weeks, and 4 weeks later. The main finding of interest was that picture recognition did not show an age-related decline until the 1-week retention interval. 相似文献
205.
206.
The goal of the authors is to (a) create an awareness among counselors about the nature and prevalence of child sexual abuse, (b) examine myths and realities about the topic, and (c) present recommendations for interviewing suspected victims of child sexual abuse. 相似文献
207.
208.
Legal and nonlegal factors influencing the civil commitment recommendations of psychologists and psychiatrists separately and as a whole were investigated using an experimental design. One hundred and seventy-six psychologists and psychiatrists made recommendations for or against commitment for a series of clinical vignettes wherein the five facets of commitment criterion, legal committability, clinical treatability, alternative resources and presence of psychosis were systematically varied. Results revealed that all facets contributed independently and in combination to the commitment decisions of participants as a whole. It was concluded that mental health professionals may utilize a variety of types of information, beyond the relevant legal criteria, in making actual decisions to initiate civil commitments. 相似文献
209.
A software package called PAST (Programmer Assessment Software Tools) is described. PAST was designed as a research and diagnostic tool to analyze how programmers develop and test program code. PAST uses line changes between successive compiles to estimate a programmer’s cognitive processing. Line changes are highlighted and graphically presented between any two versions or compiles. Summary graphs and statistics across all versions also are provided. Applications of PAST for expanding our understanding of programming and applying it to research, teaching, and learning are discussed. 相似文献
210.
High-resolution CRT displays are subject togeometric distortion: lines that are straight in the internal coordinates of the graphics software and hardware are curved when projected onto a plane in the observer’s line of sight. As the available resolution of CRT screens increases, it becomes more difficult to measure and correct for this distortion. We present a simple, highly accurate method for determining the mapping between internal coordinates and the viewing plane. It requires that an observer, using a calibration program, adjust triples of displayed points until they are collinear. A metal straightedge placed between the observer and the screen aids in this judgment. We describe the calibration of an IBM Enhanced Graphics Display in high-resolution mode (350 × 640 pixels), and illustrate how to use the estimated mapping to choose internal coordinates to draw undistorted figures that are accurate to within 0.5 pixel. The method can be used to assess or to correct the accuracy of visual displays. The method is relevant to experiments in spatial vision, spatial perception, perception of dot patterns, and any application in which geometrically accurate stimuli are required. 相似文献