首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6260篇
  免费   503篇
  国内免费   477篇
  2024年   15篇
  2023年   86篇
  2022年   78篇
  2021年   131篇
  2020年   235篇
  2019年   272篇
  2018年   238篇
  2017年   258篇
  2016年   213篇
  2015年   189篇
  2014年   253篇
  2013年   650篇
  2012年   155篇
  2011年   222篇
  2010年   211篇
  2009年   235篇
  2008年   308篇
  2007年   384篇
  2006年   361篇
  2005年   300篇
  2004年   286篇
  2003年   255篇
  2002年   209篇
  2001年   142篇
  2000年   104篇
  1999年   86篇
  1998年   53篇
  1997年   63篇
  1996年   34篇
  1995年   46篇
  1994年   25篇
  1993年   35篇
  1992年   13篇
  1991年   12篇
  1990年   7篇
  1989年   20篇
  1987年   6篇
  1985年   80篇
  1984年   112篇
  1983年   79篇
  1982年   80篇
  1981年   89篇
  1980年   70篇
  1979年   69篇
  1978年   105篇
  1977年   76篇
  1976年   80篇
  1975年   72篇
  1974年   72篇
  1973年   61篇
排序方式: 共有7240条查询结果,搜索用时 546 毫秒
141.
This study investigated the efficacy of predicting academic achievement as measured by the Wide Range Achievement Test using the factor scores of the Wechsler Intelligence Scale for Children-Revised as potential predictors. Both instruments were administered to 200 school children referred for psychological evaluations. Factor scores for the WISC-R were computed according to equations provided by Gutkin (1978). These factor scores then were regressed in a stepwise manner on the Reading, Spelling, and Arithmetic standard scores from the Wide Range Achievement Test. Stepwise regressions also were performed using the traditional Verbal and Performance IQs as the potential predictors. A comparison was made between the results obtained by use of the factors or the more common scores. The results indicated that the Freedom From Distractibility factor score significantly aided in the prediction of Reading and Spelling achievement and was of primary importance in predicting Arithmetic achievement. When the stepwise results using the different scores were contrasted, the factor scores accounted for appreaciably more variance in Arithmetic than did the traditional Verbal and Performance IQs. Derived regression equations are reported along with a discussion of the interpretability of the Freedom From Distractibility factor.  相似文献   
142.
Previous research has shown that pretreating rats with the opiate antagonist naloxone increases the freezing that follows painful electric shock. Three experiments, using freezing behavior as a dependent variable, were carried out to determine whether the drug might cause this effect by enhancing fear conditioning. Two of the studies employed a differential context fear-conditioning paradigm. Naloxone did not affect freezing behavior during the preshock adaptation period. In Experiment 1, naloxone was found to increase resistance to extinction in the S+ context. In Experiment 2, naloxone was found to increase freezing in the S+ context. This effect was dependent upon administering naloxone during training but not dependent on administering it during testing. The third study employed a generalization paradigm. It was found that naloxone's effect on postshock freezing was dependent on the place of testing; as the contextual cues of the test chamber were changed from those of the conditioning chamber, the effect of naloxone on freezing was reduced. The results of these experiments lend strong support to the hypothesis that naloxone increases freezing by enhancing the conditioning of fear to contextual stimuli associated with shock.  相似文献   
143.
Rats were trained to bar-press for water in the presence of a simultaneous compound tone-light stimulus using a discrete-trial procedure. Different groups were given between 300 and 3900 trials. When subsequently tested in extinction, all rats showed consistent levels of responding to the compound stimulus but responding to the tone and light components declined as a function of number of training trials. This is a demonstration of spontaneous configuring. Two other experiments showed that with similar procedures generalization from a component of the training stimulus to other values on the same continuum decreases with increased training with the compound stimulus. It was concluded that configuring and generalization from a single stimulus involve the same processes.  相似文献   
144.
A characterization of stochastic independence in terms of association of random variables is given. The result is applied to yield a simple proof of the Sattath-Tversky inequality without continuity assumptions.  相似文献   
145.
A procedural theory of eye movement that accounts for main features of the stochastic behavior of eye-fixation durations and direction of movement of saccades in the process of solving arithmetic exercises of addition and subtraction is presented. The best-fitting distribution of fixation durations with a relatively simple theoretical justification consists of a mixture of an exponential distribution and the convolution of two exponential distributions. The eye movements themselves were found to approximate a random walk that fits rather closely in both adult and juvenile subjects the motion postulated by the normative algorithm ordinarily taught in schools. Certain structural features of addition and subtraction exercises, such as the number of columns, the presence or absence of a carry or a borrow, are well known to affect their difficulty. In this study, regressions on such structural variables were found to account for only a relatively small part of the variation in eye-fixation durations.  相似文献   
146.
An adaptive up-down tracking procedure was used in combination with a visually reinforced head turn response to examine auditory sensitivity for 500, 2000, and 8000-Hz tone bursts in infants 6 to 18 months of age. Six- and 10-month-old infants were tested with headphone presentation of stimuli, while 10-, 14, and 18-month-olds were tested in sound field. Infant threshold estimates for both headphone and sound field were within 15 dB of adult comparisons for all frequencies and age groups. Six-month-olds were significantly less sensitive to the 8000-Hz tone than to either of the lower frequency stimuli, but older infants demonstrated approximately equal sensitivity for all three frequencies tested.  相似文献   
147.
Research by Markman (1979) suggests that children up to 12 years of age do not spontaneously detect logical inconsistencies. The present study was directed to factors which may limit children's ability to recognize their failures to understand. A task was devised which involved materials that were clearly based on children's experiences, and which involved premises and conclusions which were presented contiguously, rather than being interspersed among other sentences. Ninety-six 5-, 6-, and 7-year-old children were asked to judge the acceptability of eight three-sentence “stories” told by a puppet, and were asked to justify their responses. The stories differed in whether they were consistent or inconsistent, and in whether the principle upon which a story's consistency depended was implicitly or explicitly stated. The results showed developmental differences. By Age 7 years, most children were quite capable of evaluating sentences for their logical consistency. Five-year-olds, however, did not perform as well on the task, especially when the information upon which the logical cohesiveness of the stories rested was implicitly, rather than explicitly, stated. An examination of the justifications provided by these children revealed that they tended to question the empirical validity of individual sentences, rather than integrate the story as a whole and examine its overall logical structure.  相似文献   
148.
The hypothesis of this study is that an assumption of speaker credibility affects children's judgments of the external consistency of statements. In two experiments, first and third grade children (6 and 8 years of age, respectively) and college adults were read short paragraphs containing contradictory information from a contextual source and a speaker. The contextual source was described as either authoritative or nonauthoritative and discredited. The speaker was either an adult or child. Thus the contextual source was either more or less reliable than the speaker. Subjects were asked to affirm or contradict the speaker's statement, and to choose either the source or the speaker as most believable. The results showed that adult responses varied with the contextual source alone, while the responses of the first graders varied primarily with the speaker's age. The responses of the third graders varied with both factors. The results suggest young children can assess the external consistency of statements but frequently do not because of their assumptions about speakers and other performance factors.  相似文献   
149.
A brief historical account dealing with the concept of psychic conflict is first presented, followed by an examination of Piaget's equilibrium/equilibration model and the relevance of the concept of conflict to that model. A critical analysis of B. J. Zimmerman and D. E. Blom (Developmental Review, 1983, 3, 18–38) is then presented, after which suggestions are made regarding future directions research efforts pertaining to Piaget's conflict/learning formulation might fruitfully take.  相似文献   
150.
An observationally based assessment of social problem-solving skill was contrasted with more traditional testing methods. A preschool child with low social success was chosen for a demonstration profile analysis. The relative frequencies of the social goals, strategies, and targets shown by this child during free play were plotted in relation to that of his same-sex peer group. Parallel profiles of his relative success with specific goals, strategies, and targets were also constructed and compared to relevant group means and standard deviations. Specific social problem-solving strengths and weaknesses were identified from these profiles, using both intra- and interindividual analyses. The benefits and limitations of this approach for measurement and treatment of social problem-solving deficits were discussed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号