全文获取类型
收费全文 | 31323篇 |
免费 | 1353篇 |
国内免费 | 26篇 |
出版年
2020年 | 343篇 |
2019年 | 427篇 |
2018年 | 617篇 |
2017年 | 587篇 |
2016年 | 672篇 |
2015年 | 429篇 |
2014年 | 535篇 |
2013年 | 2437篇 |
2012年 | 999篇 |
2011年 | 1003篇 |
2010年 | 593篇 |
2009年 | 658篇 |
2008年 | 847篇 |
2007年 | 852篇 |
2006年 | 763篇 |
2005年 | 664篇 |
2004年 | 653篇 |
2003年 | 599篇 |
2002年 | 620篇 |
2001年 | 1058篇 |
2000年 | 1056篇 |
1999年 | 775篇 |
1998年 | 326篇 |
1997年 | 298篇 |
1995年 | 318篇 |
1992年 | 632篇 |
1991年 | 587篇 |
1990年 | 568篇 |
1989年 | 549篇 |
1988年 | 541篇 |
1987年 | 483篇 |
1986年 | 483篇 |
1985年 | 535篇 |
1984年 | 436篇 |
1983年 | 397篇 |
1982年 | 310篇 |
1979年 | 482篇 |
1978年 | 328篇 |
1977年 | 301篇 |
1976年 | 322篇 |
1975年 | 362篇 |
1974年 | 435篇 |
1973年 | 463篇 |
1972年 | 401篇 |
1971年 | 341篇 |
1970年 | 320篇 |
1969年 | 334篇 |
1968年 | 417篇 |
1967年 | 371篇 |
1966年 | 358篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Examination of perceptions of human facial attributes revealed that individual attributes are similarly perceived by males and females. However, patterns of attribute interrelationships differ as a function of gender of the face. Undergraduate students (N = 280) rated pictures of 40 male or female Caucasians on 12 physical attributes (e.g., nose size, face width) and overall attractiveness. The four sets of attribute ratings (defined by rater gender and picture gender) were submitted to principal components analyses, and five-factor solutions were found for each condition (accounting for about 76% of the variance). Comparisons of the four component solutions using confirmatory factor procedures revealed that male and female raters share one factor structure when rating photographs of female faces and another factor structure when rating photographs of male faces. Multiple regression analyses revealed that the patterns of attribute interrelationships were not "perceptual units" in the perception of attractiveness, and that different "rules" are used to assess the attractiveness of male and female stimuli faces. The importance of these results for models of facial attractiveness and interfacial similarity judgements are discussed. 相似文献
982.
The early versus late selection issue in attention models was examined by means of a new methodology. Through cues or precues, attention was directed to one location of a multistimulus visual display and, while attention was so engaged, the identity of a stimulus located at a different position in the display was changed. By varying the time after display onset before the stimulus was changed, we controlled the preview time that the original stimulus was represented on the retina. Then, using a marker cue, we directed the subject's attention to the location of the changed stimulus. The subject's response was a timed discrimination between two possible target letters. The data of main interest was the effect of preview time upon the subject's latency in identifying the new target that appeared in the changed location. We found that the preview time of the original stimulus, before RT was affected to the new target, depended upon whether the original stimulus was a neutral (noise) letter or whether it was the alternative target. When the original stimulus was a noise letter, RTs to the new target were just as fast as those obtained in the control condition in which the target was present throughout the preview interval and did not change its identity. Significant effects upon RT were obtained at preview times of 83 msec when the original stimulus was one of the targets that changed to the alternative target. Preview times also varied as a function of precuing. Preview times were correspondingly shortened when the first cue occurred 50 msec before display onset, thus providing an extra 50 msec for attention to be directed to the first display location. The results were interpreted in terms of two separate information-processing systems in the human: an automatic system and an attentional system. Even though a stimulus may have been automatically processed, when the attention system is directed to that stimulus, processing starts at the beginning again. 相似文献
983.
Integration psychophysics was used to explore the taste perception of mixtures of sucrose, fructose, and citric acid. Three levels of each stimulus were varied in a 3 x 3 x 3 factorial design. Subjects rated total intensity, sweetness, and acidity of the 27 mixtures on graphic rating scales. Consistent with earlier work, the perceived total intensity of the tertiary mixtures was found to be dictated by the intensity of the (subjectively) stronger component alone (i.e., either the integrated sweetness or the acidity, whichever was the more intense). In contrast, the sweetness and acidity of the mixture were susceptible to mutual suppression: Sweetness suppressed acidity, acidity suppressed sweetness. There was, however, a difference between sucrose and fructose in their interactions with citric acid, fructose being the more susceptible to suppression. This selectivity of suppression indicates that the two sweetnesses could not have been inextricably integrated. Implications for taste coding are discussed, and the findings are reconciled in terms of two separate coding mechanisms: one for taste intensity, another for taste quality. 相似文献
984.
Traditional Dental Aptitude Test and academic grade point average have been shown to be poor predictors of clinical performance by dental students. To refine predictors of psychomotor skills, a wire-bending test was given to 105 freshmen at the beginning of their dental education. Grades from seven restorative preclinical courses in their freshman and sophomore years were compared to scores on wire bending and the three traditional predictors: GPA, academic aptitude, and perceptual aptitude scores. Wire-bending scores correlated significantly with six out of seven preclinical restorative courses. The predictive power for preclinical performance was doubled when wire bending was added to traditional predictors in stepwise multiple regression analysis. Wire-bending scores identified students of low performance. These preliminary results suggest that the wire-bending test shows some potential as a screening test for identifying students who may hae psychomotor difficulties, early in their dental education. 相似文献
985.
This study is a systematic replication of the effects of insulin doses on operant behavior reinforced (in an earlier study) by fixed-ratio schedules of microwave (MW) reinforcement. In this study, insulin and dextrose doses were administered (ip) prior to fixed-interval 2-min. schedules of MW reinforcement in rats tested in a cold environment. Six Sprague-Dawley rats were conditioned to regulate their thermal environment with 5-sec. exposures of MW radiation (SAR = 0.34 Watts/kg/(mW/cm2) under the FI-2' schedules. Humulin-regular insulin and 50% solutions of dextrose were administered (ip) alternately with saline control sessions for 8-hr. durations. A within-subjects, repeated-measures 4 x 8 x 3 factorial analysis of variance design showed that insulin doses suppressed operant responding for heat, which confirmed the results of the earlier study under a different schedule. In addition, high doses of dextrose had similar suppressing effects on operant responding for heat. The data are interpreted in terms of the discriminative properties of increased thermogenesis produced by the insulin and dextrose doses. The suppressing effects were more pronounced for the first two hours, yet they persisted for approximately six hours of the 8-hr. sessions. 相似文献
986.
Pets have been shown to influence human development, but whether the effect is due to the presence of a pet or to the person's relationship with a pet is uncertain. Mothers rated their young children's companion animal bond (relationship) and social competence on a parental questionnaire, and a researcher assessed the children's empathy, cooperation, and intelligence during home visits. Significant correlations were noted between the children's bonds with their companion animals and their scores on the social competency scales as well as their empathy scores. The lack of similar significant pet presence ("ownership") correlations supports the hypothesis that the children's relationships with their pets are more important than just the presence of one or more pets in their homes. 相似文献
987.
Exposure plus response prevention has been demonstrated to be effective in the treatment of bulimia nervosa. However, when done individually, it is labor intensive and cost-ineffective. In the present study exposure plus response prevention was used in the context of a 6-wk., 12-session behavioral group. In addition to the exposure plus response-prevention component, other techniques included self-monitoring, cognitive restructuring, eating-habit stabilization and problem-solving. Eight bulimic women, vomiting a minimum of five times per week for at least a year, participated in the group. At the end of treatment significant reductions in bingeing and vomiting behaviors were reported by all but one subject, substantiated by significantly lower depression scores (Beck Depression Inventory) and binge-eating scores (Binge Eating Scale). At 6 mo. and 1 yr. posttreatment, 6 of 8 subjects reported averaging less than one binge-purge episode per week, one subject continued unchanged, and one subject had relapsed. A group of wait-list control subjects reported essentially no change in binge-purge frequency over the treatment period. Exposure plus response prevention conducted in a behavioral group context appears to be a cost-effective alternative to individual treatment. 相似文献
988.
In a comparison of religious and nonreligious psychotherapists' perceptions of a portion of a psychotherapeutic session no significant differences were found on the Vanderbilt Psychotherapy Process Scale for four groups of therapists designated according to their scores on three religious questionnaires. While the results suggest attitudes toward religion are not reflected in therapists' practice of psychotherapy, limitations of the study indicate the need for more rigorous testing of this possibility. 相似文献
989.
Joseph C. Pitt 《Studies in Philosophy and Education》1990,10(1):7-17
It is argued that the manner in which we teach science in the high schools represents an outdated positivistic conception of science. The standard presentation of a year of each of chemistry, biology and physics should be replaced by an integrated science plus history, philosophy, and sociology of science which would take a total of three years to complete. A proper appreciation for the true nature of science is essential to the continued health of the scientific enterprise. 相似文献
990.
Julia C. Jorgensen 《Journal of psycholinguistic research》1990,19(3):167-190
This paper tests psychologists' frequent assumption that dictionaries are psychologically realistic models of polysemy in the mental lexicon. Psychologists have not often explored the nature of polysemy, and lexicographers' methods have not involved scientific sampling of usages or informants. It is argued, however, that the lexicographic technique of citation sorting is an effective way of discovering sense differences. Here this technique was used in three tasks involving usage samples for 24 high- and low-frequency nouns varying widely in degree of polysemy in the dictionary. Analyses of agreement within and between subjects showed that subjects consistently judged and substantially agreed upon the major senses of most nouns, but that few nouns in either frequency group were perceived to have more than three significant senses. Additionally, the possibility that larger usage samples will bias people to make more sense groupings was found not to be true, suggesting that the larger number of senses lexicographers create for high-frequency words are not artifacts of larger usage samples.This research was partially supported by grants from the Spencer and Sloan Foundations to George A. Miller. 相似文献