全文获取类型
收费全文 | 24959篇 |
免费 | 915篇 |
国内免费 | 9篇 |
专业分类
25883篇 |
出版年
2018年 | 330篇 |
2017年 | 352篇 |
2016年 | 370篇 |
2015年 | 266篇 |
2014年 | 333篇 |
2013年 | 1788篇 |
2012年 | 593篇 |
2011年 | 637篇 |
2010年 | 436篇 |
2009年 | 397篇 |
2008年 | 622篇 |
2007年 | 555篇 |
2006年 | 543篇 |
2005年 | 462篇 |
2004年 | 467篇 |
2003年 | 472篇 |
2002年 | 481篇 |
2001年 | 638篇 |
2000年 | 647篇 |
1999年 | 509篇 |
1998年 | 258篇 |
1997年 | 274篇 |
1996年 | 272篇 |
1995年 | 259篇 |
1992年 | 490篇 |
1991年 | 456篇 |
1990年 | 448篇 |
1989年 | 417篇 |
1988年 | 443篇 |
1987年 | 407篇 |
1986年 | 454篇 |
1985年 | 431篇 |
1984年 | 383篇 |
1983年 | 336篇 |
1981年 | 270篇 |
1979年 | 409篇 |
1978年 | 331篇 |
1977年 | 284篇 |
1976年 | 296篇 |
1975年 | 342篇 |
1974年 | 436篇 |
1973年 | 471篇 |
1972年 | 343篇 |
1971年 | 369篇 |
1970年 | 334篇 |
1969年 | 364篇 |
1968年 | 441篇 |
1967年 | 400篇 |
1966年 | 422篇 |
1958年 | 253篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
Three experiments were performed to examine the role that central and peripheral vision play in the perception of the direction of translational self-motion, or heading, from optical flow. When the focus of radial outflow was in central vision, heading accuracy was slightly higher with central circular displays (10 degrees-25 degrees diameter) than with peripheral annular displays (40 degrees diameter), indicating that central vision is somewhat more sensitive to this information. Performance dropped rapidly as the eccentricity of the focus of outflow increased, indicating that the periphery does not accurately extract radial flow patterns. Together with recent research on vection and postural adjustments, these results contradict the peripheral dominance hypothesis that peripheral vision is specialized for perception of self-motion. We propose a functional sensitivity hypothesis--that self-motion is perceived on the basis of optical information rather than the retinal locus of stimulation, but that central and peripheral vision are differentially sensitive to the information characteristic of each retinal region. 相似文献
152.
Psychophysical studies with infants or with patients often are unable to use pilot data, training, or large numbers of trials. To evaluate threshold estimates under these conditions, computer simulations of experiments with small numbers of trials were performed by using psychometric functions based on a model of two types of noise: stimulus-related noise (affecting slope) and extraneous noise (affecting upper asymptote). Threshold estimates were biased and imprecise when extraneous noise was high, as were the estimates of extraneous noise. Strategies were developed for rejecting data sets as too noisy for unbiased and precise threshold estimation; these strategies were most successful when extraneous noise was low for most of the data sets. An analysis of 1,026 data sets from visual function tests of infants and toddlers showed that extraneous noise is often considerable, that experimental paradigms can be developed that minimize extraneous noise, and that data analysis that does not consider the effects of extraneous noise may underestimate test-retest reliability and overestimate interocular differences. 相似文献
153.
W Prinzmetal 《Perception & psychophysics》1992,51(5):473-484
Six experiments examined the possibility of obtaining a word-superiority effect (WSE) without the use of brief stimulus exposures or a poststimulus mask. In each experiment, subjects were presented a stimulus string and two alternative strings that differed by a single letter (Reicher, 1969). The alternatives and stimulus remained in view until subjects responded, and subjects were under no pressure to respond quickly. In Experiments 1-3, the stimuli were presented in very small type so that they were difficult to see. Subjects were significantly more accurate with words than with nonwords, letters embedded among digits, or letters embedded among number signs (#s). In Experiments 4 and 5, the stimuli were embedded in a simultaneously present pattern mask. Subjects were significantly more accurate with words than with single letters by themselves. In the final experiment, the stimuli were presented in a mask with specific spatial frequency characteristics, and performance was significantly better with words than with nonwords. The WSE is a more general phenomenon than previously supposed; it is not limited to a tachistoscopic exposure. 相似文献
154.
A soft contact-lens system for achieving unilateral visual stimulation in a free vision format is described. Initial testing with light transmittance and visual perimetry indicated that the lenses created artificial visual-field deficits. The efficacy of the lenses as a technique for lateralizing visual input was evaluated by examining within-subject differences in performance on two visuospatial tasks. Speed and accuracy of performance were greater with visual input directed to the right hemisphere. These data support the lens design as a useful alternative to tachistoscopic procedures and previous lens systems. 相似文献
155.
W Fals-Stewart 《Perceptual and motor skills》1992,75(1):244-246
The subtests of the Brain Age Quotient, a brief neuropsychological battery, were used to screen for cognitive impairment in a sample of 112 substance abusers. Each of the subtests was scored, using newly developed T scores corrected for age, education, and gender, for which a mean battery score of T less than 40 indicates general cognitive impairment. The chance-corrected agreement in finding cognitive dysfunction between this battery and the Average Impairment Rating T score from the Halstead-Reitan battery was adequate, kappa = .81. This result suggests that, for discerning global cognitive impairment, this relatively brief neurodiagnostic screening device may be an attractive alternative to the more time-consuming Halstead-Reitan battery. 相似文献
156.
The Profile of Mood States was printed on four different colors of paper (yellow, red, green, blue) and white to test whether the color of paper would influence mood state scores of 246 college students. Univariate analyses of variance identified color effects only on the Fatigue scale. 相似文献
157.
This empirical study was undertaken to clarify controversial points emanating from previous theoretical and empirical papers dealing with apparently negative consequences on the personality development of young people who have at least a causal working-acquaintance with computers. We tested 174 persons of both sexes (age: 14-18 years) with a "Computer-Attitude-Questionnaire" and the "Mehrdimensionaler Pers?nlichkeitstest für Jugendliche" (Schmidt, 1981; "Multidimensional-Personality-Test"). A subgroup of 63 persons who have access to and do avail themselves of computers on a regular basis (as leisure-time activity) also answered the "Computer-Motive-Questionnaire". Statistical analyses revealed that the personality test-values of young people with a positive attitude toward computers range within the test-norm. The data for these people describe them as stress resistant, emotionally stable, well-balanced, sociable, achievement-oriented, and less aggressive. 相似文献
158.
B P McCloskey R L Klatzky J W Pellegrino 《Journal of experimental psychology. Human perception and performance》1992,18(4):948-961
Previous research (Klatzky et al., 1989) shows that the time required to make sensible/nonsensible judgments about an action-object phrase (e.g., "rub your stomach") is reliably faster when the phrase is preceded by a cure representing a specific prototypical hand shape (vs. a neutral cue). The current experiments investigated the effects of preparing for an alternate task (finger tapping vs. syllable vocalization) on facilitatory priming of sensibility judgments. Preparation for finger tapping reduced the magnitude of the priming effect more than preparation for vocalization, suggesting that resources accessed during semantic processing of action-object phrases are also used during manual response preparation. The results support the existence of a system representing manual actions that is limited in the number of activities that can be represented at one time and that is not so general that it represents manual and vocal tract movements. 相似文献
159.
David A. Julian Teresa W. Julian Barry J. Mastrine Pauline Wessa Elizabeth Atkinson 《American journal of community psychology》1992,20(6):799-809
Analyzed case records to determine the costs and service usage patterns for a group of 25 youth randomly selected from the case load of a regional mental health agency. Study participants had extensive histories of publicly supported psychiatric hospitalizations. An average of 36.2 contacts per youth (905 total contacts) with human services providers were documented. Approximately 2 out of every 5 contacts resulted in out-of-home placements. The estimated cost of providing services to the 25 youth exceeded 3 million dollars. The types and costs of treatment services provided to study participants are discussed. 相似文献
160.
A short-term longitudinal study was conducted to determine whether self-regulation at 4 years could be predicted from child and maternal measures obtained when the children were age 24 months. The subjects were 69 children and their mothers drawn from the general community. Criterion behaviors assessed at 4 years were those suggestive of attention-deficit hyperactivity disorder. Of the 24-month child measures, maternal ratings of the child's impulsivity and attention span, plus an objective measure of delay ability, were the most effective predictors. Maternal negativity, as assessed in mother-child interaction, predicted the criterion behaviors, even after the child's behavior as an elicitor of maternal behavior was controlled. Maternal child-rearing attitudes on the dimensions of warmth and aggravation were also effective predictors, even after controlling for the child's emotionality as a possible determinant of maternal attitudes. It is argued that the results with the maternal attitude measures provide support for the hypothesis that maternal behavior is a contributor to the development of self-regulation.This research was supported by a State of Ohio Academic Challenge Grant to the Bowling Green State University Clinical Psychology Program, and by a Basic Grant awarded to the first author by the Bowling Green State University Faculty Research Committee. The authors are grateful to Eric Dubow, Douglas Ullman, and two anonymous reviewers for their helpful comments and criticisms on previous versions of this article. 相似文献