全文获取类型
收费全文 | 31339篇 |
免费 | 1135篇 |
国内免费 | 12篇 |
专业分类
32486篇 |
出版年
2019年 | 318篇 |
2018年 | 487篇 |
2017年 | 490篇 |
2016年 | 494篇 |
2015年 | 348篇 |
2014年 | 457篇 |
2013年 | 2304篇 |
2012年 | 813篇 |
2011年 | 840篇 |
2010年 | 543篇 |
2009年 | 518篇 |
2008年 | 794篇 |
2007年 | 749篇 |
2006年 | 687篇 |
2005年 | 609篇 |
2004年 | 618篇 |
2003年 | 597篇 |
2002年 | 638篇 |
2001年 | 864篇 |
2000年 | 845篇 |
1999年 | 647篇 |
1998年 | 331篇 |
1997年 | 332篇 |
1996年 | 342篇 |
1995年 | 313篇 |
1992年 | 603篇 |
1991年 | 570篇 |
1990年 | 560篇 |
1989年 | 517篇 |
1988年 | 530篇 |
1987年 | 502篇 |
1986年 | 543篇 |
1985年 | 531篇 |
1984年 | 474篇 |
1983年 | 409篇 |
1981年 | 321篇 |
1979年 | 491篇 |
1978年 | 400篇 |
1977年 | 344篇 |
1976年 | 344篇 |
1975年 | 397篇 |
1974年 | 509篇 |
1973年 | 556篇 |
1972年 | 411篇 |
1971年 | 428篇 |
1970年 | 411篇 |
1969年 | 433篇 |
1968年 | 536篇 |
1967年 | 472篇 |
1966年 | 502篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
891.
Marked differences in detectability as a function of spatial location, a "detectability gradient," are observed when subjects are required to detect a briefly exposed target pattern of uncertain location in the presence of a number of nontarget patterns. Target detectability also is inversely related to the number of nontarget patterns which are present in this search paradigm. These previous findings provide strong evidence for a serial process in which increasing probability of error occurs during a scan of a rapidly degrading neural representation of the visual image following a brief exposure to the stimuli. It is not yet established whether this scan is attentional or perceptual in nature. The present experiments test the hypothesis of an attentional scan by presenting the target and nontarget patterns in spatially segregated groups. If the scan is attentional, then target detectability under these circumstances would be expected to exhibit the characteristic phenomenon of "group processing"--a close clustering of detection performance for targets located within a group and large differences in detectability across groups. As no evidence for group processing was observed, the results fail to support the view that the scan is attentional in nature but are fully consistent with a nonattentional scan. 相似文献
892.
Long-term effects of cerebellar pathology on cognitive functions 总被引:3,自引:0,他引:3
Twelve patients with circumscribed chronic neocerebellar lesions but without CT-evidence of forebrain damage (other than the effects of shunting) were investigated for deficits of cognitive functions. Two different mechanisms were considered as possible causes of cognitive impairment: (1) Damage to the dentato-thalamo-cortical projection leading to impairments of cortical functions, and (2) prolonged intracranial pressure resulting in diffuse forebrain damage and subcortical dementia. Patients with lesions in the left neocerebellum showed deficits in cognitive operations in three dimensional space, consistent with the right forebrain dominance for spatial functions. Prolonged intracranial pressure, on the other hand, resulted in a mild overall cognitive impairment. 相似文献
893.
Previous experiments in this laboratory employing a search paradigm have found highly significant differences in the detectability of a briefly exposed target pattern as a function of the spatial location of the target when it is presented simultaneously with a number of discriminably different nontarget patterns. These detectability differences, at loci equidistant from the fovea, could not be accounted for by any known variation in retinal spatial resolution or by differential lateral masking effects of the target by nearby nontarget patterns. These observations led to the hypothesis that the target in these experiments was detected by a serial mechanism which "scanned" a persisting but rapidly degrading neural representation of the visual scene with increasing detection failures the later in time the scan processed the location occupied by the target. If this hypothesis is correct, then target detectability should vary inversely with the number of stimuli which must be examined. The present experiment confirmed this expectation. A mathematical model of such a serial scanning process also predicts other, less obvious, effects on target detectability which were observed when the number of nontarget patterns was changed. 相似文献
894.
Summary When a line (the pointer) is collinear with a dot, the addition of a second line (the induction line) contiguous with the dot or near it may cause the pointer to appear to be collinear with a point further along or nearer to the induction line. The geometrical relations upon which this effect, which we call attraction-caused misalignment, depends have been studied with the Obonai and Wundt-Loeb (Hotopf, 1981; Hotopf & Brown, 1988) figures. Drawing upon the studies of misalignment in the Morinaga figure carried out by Restle (1976), Day, Bellamy, and Norman (1983), and Day and Kasperczyk (1985), as well as upon two new experiments, we show that misalignment in the Morinaga figure is also attraction-caused misalignment, as previously defined. We conclude with a discussion of a number of theories that aim at accounting for attraction misalignment. 相似文献
895.
The relationship between sex role flexibility and prosocial behavior among preschool children was investigated. Subjects included 16 boys and 18 girls, ranging in age from 36 to 60 months, from intact families of the upper middle class. A nonhierarchical multiple regression analysis was undertaken to determine the contributions of the predictor variables of sex, age, IQ, and sex role flexibility, as well as their interactions with prosocial behavior (criterion variable). Results indicated that while the overall regression model was not significant, the variable of Sex × Sex Role Flexibility did contribute significantly to the model. Inspection of the correlation coefficients associated with this variable revealed that while sex role flexibility and prosocial behavior among boys were significantly and positively related, among girls no significant relationship was found. 相似文献
896.
Properties of memory for unattended spoken syllables 总被引:1,自引:0,他引:1
N Cowan W Lichty T R Grove 《Journal of experimental psychology. Learning, memory, and cognition》1990,16(2):258-269
Whereas previous studies on memory for unattended speech have inadvertently included acoustic interference, the present study examines memory for unattended syllables during a silent period of 1, 5, or 10 s. The primary task was to read silently (Experiments 1-3) or whisper the reading (Experiment 4). Occasionally, when a light cue occurred, the subject was to recall the most recent spoken syllable, as well as the recent reading material. Memory for both the vowels and consonants of the syllables decreased across 10 s, confirming that auditory memory does decay in the absence of acoustic interference. However, the specific patterns of memory decay for vowels versus consonants depended on task demands, including the allocation of attention and the opportunity for subvocal coding. We suggest an account of performance that includes auditory sensory and phonetic memory codes with different properties, used in combination. 相似文献
897.
Rev. Arlin Roy M.S.W. 《Group》1990,14(1):59-64
Family rituals express patterned, repeated, symbolic communication that is ordered, evocative, socially meaningful, and directly impacts upon family functioning. Seasonal celebrations, rites of passage, family traditions, and patterned family interactions serve to organize the family, mediate individual expectations, regulate family subsystems, and facilitate change. Clergy and psychotherapists can use an understanding of family rituals to better understand individuals in their family context, promote change through prescribing rituals, and help clients create new, healing rituals. 相似文献
898.
It was hypothesized that older widows (N=309) who had been care givers to their husbands would have undertaken a greater number of household responsibilities than had women who had not been care givers. Findings indicated that, prior to the husband's death, more traditionally male and more traditionally female tasks were performed by the care-giving wives (n=158). This was particularly true in the case of Alzheimer's care givers (n=21). More importantly, widows' present feelings of competence were related to undertaking household responsibilities, with those who had been care givers expressing significantly higher levels of competence. 相似文献
899.
Alternate 25-item short forms of the Sex-Role Egalitarianism Scale (SRES) were developed and examined for psychometric quality using data from a sample of 608 students. Internal consistency coefficients were .94 and .92 for the two forms, stability coefficients with a three-week test-retest in terval were .88 for each, and the coefficient of equivalence or alternate forms reliability was .87. As expected, females scored significantly more egalitarian than males on both short forms, and results of factor analyses pointed to unidimensional measurement of a single construct for males, females, and the total sample. Additional support for reliability and validity is overviewed. The abbreviated SRES forms appear to provide a psychometrically sound and time-efficient means for assessing egalitarian attitudes. 相似文献
900.
This study was designed to examine the correlates of developmental psychological stress for 36 middle-aged professional men. Based on sex role convergence and role adjustment theories, two sets of predictor variables were hierarchically entered into a multiple regression equation with a third set of variables entered to control for individual stressors. Controlling for individual stressors, midlife stress outcome was found to be influenced only by role adjustment (R2=.3593). The sex role convergence cluster did not account for a significant increase in variance. Controlling for individual stressors, the best univariate predictors of stress outcome associated with the midlife transition were (a) the quality of the parent-adolescent relationship and (b) marital satisfaction. 相似文献