全文获取类型
收费全文 | 50143篇 |
免费 | 2057篇 |
国内免费 | 34篇 |
出版年
2020年 | 515篇 |
2019年 | 649篇 |
2018年 | 913篇 |
2017年 | 914篇 |
2016年 | 1027篇 |
2015年 | 713篇 |
2014年 | 842篇 |
2013年 | 3957篇 |
2012年 | 1537篇 |
2011年 | 1565篇 |
2010年 | 924篇 |
2009年 | 976篇 |
2008年 | 1274篇 |
2007年 | 1355篇 |
2006年 | 1166篇 |
2005年 | 1049篇 |
2004年 | 1012篇 |
2003年 | 952篇 |
2002年 | 988篇 |
2001年 | 1666篇 |
2000年 | 1624篇 |
1999年 | 1223篇 |
1998年 | 512篇 |
1996年 | 490篇 |
1995年 | 480篇 |
1992年 | 1003篇 |
1991年 | 947篇 |
1990年 | 937篇 |
1989年 | 877篇 |
1988年 | 882篇 |
1987年 | 802篇 |
1986年 | 818篇 |
1985年 | 861篇 |
1984年 | 698篇 |
1983年 | 628篇 |
1982年 | 493篇 |
1979年 | 784篇 |
1978年 | 557篇 |
1977年 | 492篇 |
1976年 | 490篇 |
1975年 | 611篇 |
1974年 | 749篇 |
1973年 | 784篇 |
1972年 | 654篇 |
1971年 | 597篇 |
1970年 | 577篇 |
1969年 | 561篇 |
1968年 | 714篇 |
1967年 | 625篇 |
1966年 | 591篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
The present study examined some previously reported relationships between drug use by adolescents and perceived attitudes and behaviors of their parents. An anonymous questionnaire was administered to the student body of an inner-city secondary school for difficult students. Relationships between parental use of drugs and adolescent use of the same drugs were moderate and roughly equivalent across drugs. However, parental use of marijuana was strongly related to the adolescent's use of other, harder drugs such as opiates, cocaine, amphetamines, and barbiturates. This finding is explained within the framework of Kandel's postulated stages of drug initiation. It points to a need for further study of parental influences, which may be increasingly problematic as more individuals who have grown up in our marijuana-accepting society become parents of adolescents. 相似文献
982.
Richard A. Schmidt Stan C.A.M. Gielen Pieter J.M. Van Den Heuvel 《Acta psychologica》1984,57(2):145-164
When an imperative visual stimulus is paired with an auditory (accessory) stimulus, RT is generally faster than with the imperative stimulus alone. Three experiments using additive-factors logic tested an energy-summation view of the accessory, where effects are due to increased rate of information build-up in sensory stages, and a preparation-enhancement view which holds that the accessory serves an alerting function. Experiment 1 found no interaction between the accessory presence and (visual) stimulus brightness, suggesting no role of the accessory in stimulus identification. Experiment 2 found no interaction between accessory presence and spatial S-R compatibility, arguing that the accessory operated in stage(s) other than response selection. Experiment 3 produced an interaction between the accessory and movement complexity, arguing for accessory effects in a response-programming stage. The data generally favored preparation-enhancement, and offered no support for an energy-summation view. 相似文献
983.
The authors recently proposed that adverse effects of material rewards on Wechsler subscale performance may be the result of a reward-produced developmental regression. The present study further explores that idea through an attempt to replicate earlier findings with adults and to extend the inquiry to children. Selected Wechsler subscales were administered to 32 subjects at each of three ages (5, 10, and 18 years) under either reward or nonreward conditions. Subscales were chosen to represent both algorithmic and heuristic types of tasks. Reward and nonreward groups (8 males and 8 females per group at each age) were matched initially on age and ability. For adults, consistent with earlier findings, reward had an adverse effect on performance on the heuristic subscales and tended to facilitate performance on the algorithmic subscales. However, rewards generally had no effect at the fourth-grade level and had a reverse effect at the nursery school level, i.e., rewards facilitated heuristic and hampered algorithmic performance. These findings appear to be more consistent with an explanation based on developmental regression than on any available alternative mechanism. 相似文献
984.
985.
Rutherford B. Porter 《Journal of School Psychology》1984,22(3):223-231
This report relates personal experiences as they influenced the emerging role of the school psychologist, especially in Pennsylvania and Indiana from 1930 to 1970. 相似文献
986.
Orthogonal and oblique factor analyses were performed using the Wechsler Adult Intelligence Scale-Revised (WAIS-R) standardization sample (Wechsler, 1981). Using objective criteria, it was decided to retain two factors. Evidence for a strong general intelligence (g) factor was found from both the orthogonal and oblique rotations. Whereas the verbal IQ provided an acceptable estimate of the Verbal Comprehension factor, a purer measure was found in the form of a Verbal Comprehension Deviation Quotient containing only the Information, Vocabulary, Comprehension, and Similarities subtests. The performance IQ was found to be an inadequate measure of the Perceptual Organization factor. A Perceptual Organization Deviation Quotient, containing only the Block Design and Object Assembly subtests, was recommended as an effective alternative. Analysis of the variance components for each subtest at every age level revealed that a substantial proportion of subtests at a wide range of age levels evidence either high or intermediate levels of specific variance. These results are discussed in terms of interpreting individual subtest scores and patterns. Each of the study's major findings are compared with prior work done with the Wechsler Adult Intelligence Scale (WAIS) (Wechsler, 1955). 相似文献
987.
David P. Lindeman Henry A. Goodstein Arlene Sachs Clifford C. Young 《Journal of School Psychology》1984,22(1):111-117
The purpose of the present study was to evaluate the predictive validity of the Yellow Brick Road Test (YBRT) relative to performance in reading as measured by the Metropolitan Achievement Test (MAT). A full prediction-performance comparison matrix was employed to compare three different cutoff scores for the YBRT for the identification of “at-risk” children. Four hundred and fourteen kindergarten-aged children were administered the YBRT, 214 of whom were followed to the end of second grade. It was concluded that the YBRT is a moderately valid instrument for predicting the level of reading achievement in a population with a different average performance level from the normative sample. However, the results of this study failed to support the utility of the test author's suggested use of a score of 120 as the cutoff score. Finally, it is recommended that a prediction-performance comparison study be considered standard methodology for the evaluation of the validity and efficiency of screening instruments. 相似文献
988.
B F Skinner 《Journal of the experimental analysis of behavior》1984,41(2):217-221
989.
Catania AC 《Journal of the experimental analysis of behavior》1984,42(2):165-169
990.
Rats' lever pressing produced sucrose reinforcers on a variable-interval schedule where, in different conditions, the duration of a stimulus presented immediately after reinforcement was either correlated or uncorrelated with the duration of the current interreinforcement interval. Under the baseline schedule, in which no stimulus was presented, the minimum interreinforcement interval was 8 s and the mean postreinforcement pause of each subject approximated this value. Response rates increased slowly over the first 10 to 15 s and then remained roughly constant throughout the remainder of the interval. In both the correlated and uncorrelated conditions, the added stimulus resulted in the postreinforcement pauses lengthening to values in excess of the duration of the preceding stimulus. This resulted in a poststimulus pause which was, in most cases, roughly constant irrespective of the duration of the preceding stimulus, or of the reinforcement contingencies prevailing immediately after stimulus offset. Local response-rate patterns in the uncorrelated conditions were similar to those obtained under the baseline schedule in which no stimulus was presented. However, in the correlated condition local response rates increased across the remainder of the interreinforcer interval. Further, the rate of acceleration was inversely related to the duration of the preceding stimulus. These results show that a correlation between stimulus duration and the ensuing time to reinforcement can control behavior—a type of temporal control not previously reported. 相似文献