全文获取类型
收费全文 | 76596篇 |
免费 | 2982篇 |
国内免费 | 25篇 |
专业分类
79603篇 |
出版年
2020年 | 721篇 |
2019年 | 905篇 |
2018年 | 1243篇 |
2017年 | 1307篇 |
2016年 | 1361篇 |
2015年 | 967篇 |
2014年 | 1164篇 |
2013年 | 5652篇 |
2012年 | 2202篇 |
2011年 | 2419篇 |
2010年 | 1492篇 |
2009年 | 1469篇 |
2008年 | 2103篇 |
2007年 | 2129篇 |
2006年 | 1929篇 |
2005年 | 1719篇 |
2004年 | 1606篇 |
2003年 | 1510篇 |
2002年 | 1657篇 |
2001年 | 2464篇 |
2000年 | 2443篇 |
1999年 | 1846篇 |
1998年 | 886篇 |
1997年 | 780篇 |
1996年 | 762篇 |
1992年 | 1559篇 |
1991年 | 1438篇 |
1990年 | 1454篇 |
1989年 | 1343篇 |
1988年 | 1318篇 |
1987年 | 1256篇 |
1986年 | 1342篇 |
1985年 | 1364篇 |
1984年 | 1135篇 |
1983年 | 1039篇 |
1982年 | 748篇 |
1981年 | 734篇 |
1979年 | 1214篇 |
1978年 | 876篇 |
1977年 | 731篇 |
1975年 | 1054篇 |
1974年 | 1108篇 |
1973年 | 1169篇 |
1972年 | 1008篇 |
1971年 | 933篇 |
1970年 | 848篇 |
1969年 | 924篇 |
1968年 | 1116篇 |
1967年 | 1011篇 |
1966年 | 909篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
951.
We describe a distributed model of information processing and memory and apply it to the representation of general and specific information. The model consists of a large number of simple processing elements which send excitatory and inhibitory signals to each other via modifiable connections. Information processing is thought of as the process whereby patterns of activation are formed over the units in the model through their excitatory and inhibitory interactions. The memory trace of a processing event is the change or increment to the strengths of the interconnections that results from the processing event. The traces of separate events are superimposed on each other in the values of the connection strengths that result from the entire set of traces stored in the memory. The model is applied to a number of findings related to the question of whether we store abstract representations or an enumeration of specific experiences in memory. The model simulates the results of a number of important experiments which have been taken as evidence for the enumeration of specific experiences. At the same time, it shows how the functional equivalent of abstract representations--prototypes, logogens, and even rules--can emerge from the superposition of traces of specific experiences, when the conditions are right for this to happen. In essence, the model captures the structure present in a set of input patterns; thus, it behaves as though it had learned prototypes or rules, to the extent that the structure of the environment it has learned about can be captured by describing it in terms of these abstractions. 相似文献
952.
J Cranney M E Cohen H S Hoffman 《Journal of experimental psychology. Animal behavior processes》1985,11(1):112-119
In laboratory rats (as in humans) a low-intensity tone that precedes a high-intensity burst of noise by approximately 100 ms can reduce the amplitude of the startle reaction elicited by the burst of noise. A series of four experiments with rats investigated the relation between the inhibitory effects of tonal frequency change and the length of the silent period (gap) preceding it. The major findings were the following: (a) A gap in an otherwise continuous pure tone inhibited startle when the gap occurred approximately 100 ms prior to the noise burst. (b) Although an increase in gap duration increased the inhibition afforded by the gap, the maximum inhibition was yielded by gaps of 100 ms and greater; this maximum was equivalent to the inhibition yielded by the presentation of a postgap tone alone. (c) A shift in tonal frequency across a 10-ms gap yielded more inhibition than did the same gap with no frequency shift; again the shift yielded equivalent inhibition to the presentation of the postgap tone alone. (d) An increase in the frequency shift increased inhibition when the shift occurred across a 10-ms gap, but not when the shift occurred across a 100-ms gap. 相似文献
953.
Observers detected a briefly flashed target letter embedded in word, pronounceable nonword, and unpronounceable nonword contexts. The word context facilitated perception under both holistic and analytical processing strategies; the facilitative effect was enhanced when processing was analytical. 相似文献
954.
P J Urcuioli 《Journal of experimental psychology. Animal behavior processes》1985,11(4):502-519
Pigeons were trained on matching-to-sample (MTS) with differential sample-response requirements that were identical with respect to two pairs of sample stimuli but were either correlated or uncorrelated with correct choice. Experiment 1A showed that birds in the uncorrelated condition were slower to reach criterion levels of accuracy than birds in the correlated condition in spite of their equivalent sample discriminations. However, correlated birds were more disrupted in their matching performances than the uncorrelated birds when subsequently switched to nondifferential sample-response requirements (Experiment 1B). Experiment 2 showed that differential sample behaviors also generated higher levels of accuracy on delayed MTS when correlated with choice, and that accuracy in this condition did not differ as a function of whether the samples were hues or lines. Sample dimension did affect memory performance, on the other hand, in the uncorrelated condition. In Experiment 3, reversing differential sample-response requirements for one pair of samples substantially reduced matching accuracy in the correlated group but had almost no effect in the uncorrelated group. These findings demonstrate that differential sample behaviors directly control pigeons' matching performances and also overshadow conditional stimulus control by the samples when these behaviors are predictive of correct choice. The facilitation in matching produced by differential sample behaviors apparently arises from the additional cue these behaviors provide, not because they enhance sample discriminability. 相似文献
955.
956.
The purpose of this study was to determine the extent to which stutters manipulate vowel duration to achieve fluency after participating in Precision Fluency Shaping. Nine stutterers who read an all-voiced sentence fluently before and after therapy were selected for study. Wide-band spectrograms were made of the initial phrase of the sentences, and vowel durations were computed. Results indicated that extended vowel durations were characteristic of the fluency of stutterers posttherapy. The subject that had the highest rate of disfluency after therapy also had the shortest vowel durations. Clinical implications concerning the importance of speech rate during carryover practice are made. 相似文献
957.
G Calhoun 《Adolescence》1987,22(88):939-943
Bibliotherapy has been used for generations by professionals in medicine, psychology, counseling, social work, and education. A selected review of the literature is provided to show how bibliotherapy was used in the past and how it is currently employed to implement and facilitate self-identification and to enhance self-perception. Researchers concur that the process of providing pupils with carefully monitored literature will result in positive or negative changes in their self-perception. 相似文献
958.
Keeping juvenile delinquents in school: a prediction model 总被引:1,自引:0,他引:1
The purpose of this study was to test an empirically based prediction model of school dropout on a sample of 137 juvenile delinquents, some who have dropped out and some who have remained in school. The specific factors among the many found in previous research that are salient for predicting whether delinquent youths will drop out or remain in school were determined. An important finding of this study is that it required only four factors to yield a high level of prediction: misbehavior in school, disliking school, the negative influence of peers with respect to dropping out and getting into trouble, and a marginal or weak relationship with parents. The four factors identified create a model that is directly applicable to prevention strategies and is extremely parsimonious. 相似文献
959.
960.
The Extended Objective Measure of Ego Identity Status (EOM-EIS) was examined for reliability and validity among early/middle adolescent subjects. The EOM-EIS represents a combination of the Objective Measure of Ego Identity Status and a structured interview of identity status. The instrument was designed to measure ego identity with regard to occupational, religious, political, philosophical, and social contexts along ideological and interpersonal dimensions. A total of 467 students aged 12 to 18 (median = 15.73) responded to the instrument. In general the results from the analyses of reliability, validity, demographic characteristics, and psychosocial maturity yielded results which parallel the theoretical framework and the results from college-aged subjects. 相似文献