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   86670篇
  免费   2911篇
  国内免费   31篇
  2020年   871篇
  2019年   1047篇
  2018年   4485篇
  2017年   3906篇
  2016年   3485篇
  2015年   1275篇
  2014年   1435篇
  2013年   6361篇
  2012年   2957篇
  2011年   4553篇
  2010年   3749篇
  2009年   2880篇
  2008年   3690篇
  2007年   4070篇
  2006年   2037篇
  2005年   1910篇
  2004年   1873篇
  2003年   1776篇
  2002年   1645篇
  2001年   2193篇
  2000年   2078篇
  1999年   1588篇
  1998年   829篇
  1997年   739篇
  1996年   789篇
  1995年   716篇
  1994年   698篇
  1993年   669篇
  1992年   1255篇
  1991年   1157篇
  1990年   1128篇
  1989年   1072篇
  1988年   1027篇
  1987年   976篇
  1986年   990篇
  1985年   1062篇
  1984年   882篇
  1983年   760篇
  1982年   600篇
  1981年   597篇
  1979年   853篇
  1978年   683篇
  1977年   583篇
  1976年   578篇
  1975年   707篇
  1974年   789篇
  1973年   792篇
  1972年   668篇
  1971年   615篇
  1968年   653篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
891.
892.
The relationship of characteristics of the social environment to the adaptation of adolescents from high-risk predisposing environments was examined. Specifically, the degree to which adolescents' perceptions of various dimensions of their family and school environment as well as sources of social support related to differential levels of personal well-being and academic adjustment was explored. Multiple regression analyses revealed differences in the salience of the dimensions of the social environment as a function of the particular sphere of functioning under consideration. Implications of the findings for developing a model for understanding the relative vulnerability of individuals at risk as well as of the design of preventive interventions are discussed.  相似文献   
893.
Recent evidence suggests that people are sensitive to the degree of contingency between their actions and ensuing outcomes, but little is known about the way in which such contingency judgments develop as more and more information about the contingency is provided. Three experiments examined this issue in the context of a video game. In Experiment 1, it was found that contingency judgments follow growth functions: When the contingency was positive, judgments increased toward a positive asymptote, and when the contingency was negative, judgments decreased toward a negative asymptote. When the contingency was zero, judgments themselves remained close to zero but were biased by the overall frequency with which the outcome occurred. In Experiment 2, it was shown that the growth function was not the result of the anchoring of early judgments at the zero point. The bias in judgments when the contingency is zero was investigated in Experiment 3. The results are discussed in terms of rule-based analyses and contemporary theories of conditioning.  相似文献   
894.
In his theorizing about self-actualization, Maslow speculated that physical ability and physical self-confidence were two aspects of cooperative dominance which were associated positively with actualization. These aspects of dominance bear close resemblance to the Perceived Physical Ability (PPA) and the Physical Self-Presentation Confidence (PSPC) dimensions of the Physical Self-Efficacy (PSE) Inventory. Accordingly, the PPA and PSPC scores of undergraduate men and women were correlated with their scores on the Personal Orientation Inventory (POI), a popular measure of actualization, to test Maslow's hypotheses. The results showed that, contrary to Maslow's claims, PPA is not a positive correlate of self-actualization. However, strong support was found for Maslow's contention that high-PSPC individuals are more likely to be actualizing than low-PSPC people. Also, Maslow's hypothesis that actualizers are high in global sensation seeking (SS) was tested. The data indicated that only male actualizers were high in various aspects of SS, but female actualizers were not. Multiple regression analyses revealed further that both SS and PSPC are primary contributors to POI for men, but only PSPC contributes significantly to POI for women. Discussion focused on the reasons why research findings showing that increases in physical fitness lead to increases in self-esteem cannot be used to support the view that physical fitness and actualization are linked positively.  相似文献   
895.
The present experiments examined the effects of self-focus, as produced by focusing on feelings, on memory. In an initial experiment subjects did complex mental arithmetic significantly faster after self-focus. Because complex mental addition involves internally generated stimuli, the remaining experiments compared the effects, on memory, of self-focus on internally generated stimuli to the effect of self-focus on stimuli supplied by the experimenter. In a second experiment, self-focus facilitated memory for digits recalled in reverse order but not for digits when recalled in the given order. In a third experiment, self-focus facilitated the memory for the classification of digits but not for the digits themselves. In a fourth and fifth experiment, self-focus aided memory for classification of objects into categories such as small, medium, or large but did not aid memory for the objects themselves. In general, improved performance due to feeling focus was attributed to the role that self-focus may play in increasing attention to internally generated stimuli.  相似文献   
896.
The reading performance of a Japanese Broca-type aphasic patient on a single-word reading test was investigated. The result indicated that the subject fits the symptom complex of deep dyslexia in more than one aspect. Unique characteristics of this subject included (1) the isolated subcortical site of the lesion, which apparently produced deep dyslexia, and (2) double dissociations between kanji and kana processing and between oral reading and reading comprehension. The performance of this subject was compared with that of another Japanese deep dyslexic subject in S. Sasanuma (1980, In M. Coltheart, K. Patterson, & J. C. Marshall (Eds.), Deep dyslexia, London: Routledge & Kegan Paul). A theoretical implication was attempted based on a dual coding process scheme by S. Sasanuma and O. Fujimura (1978, Cortex, 7, 1-18).  相似文献   
897.
Subjects performed a visual target-detection task in eight experiments. We examined the effects of word relevancy (word in relevant or irrelevant location) and display load (1-4 words) on physical, semantic, and controlled processing of nontargets. Interwoven with the detection task was a test-word identification task that was used to measure priming potency of nontargets. Physical and semantic levels of processing were measured in terms of identity and semantic priming, respectively. Nontarget primes were repeated as test words in identity priming. Nontarget primes were semantic associates of test words in semantic priming. Controlled processing of nontargets was measured in terms of recognition memory on a subsequent test. All measures increased with word relevancy and decreased with display load. The priming effects remained intact even when word presentation was speeded up and controlled processing was sharply curtailed. The data indicate that all levels of processing are selective and capacity limited.  相似文献   
898.
Recent efforts to build computer simulation models of mental imagery have suggested that imagery is not a unitary phenomenon. Rather, such efforts have led to a modular analysis of the image-generation process, with separate modules that can activate visual memories, inspect parts of imaged patterns, and arrange separate parts into a composite image. This idea was supported by the finding of functional dissociations between the kinds of imagery tasks that could be performed in the left and right cerebral hemispheres of two patients who had previously undergone surgical transection of their corpus callosa. The left hemisphere in both subjects could inspect imaged patterns and could generate single and multipart images. In contrast, although the right hemisphere could inspect imaged patterns and could generate images of overall shape, it had difficulty in generating multipart images. The results suggest a deficit in the module that arranges parts into a composite. The observed pattern of deficits and abilities implied that this module is not used in language, visual perception, or drawing. Furthermore, the results suggest that the basis for this deficit is not a difficulty in simply remembering visual details or engaging in sequential processing.  相似文献   
899.
Six experiments with rats used a psychophysical choice procedure to study the internal clock used to discriminate duration. They investigated if the clock is sensitive to the signal value (associative strength) of a stimulus. The experiments involved two types of trials. On choice trials, a stimulus lasted a short (e.g., 3 s) or long (e.g., 12 s) duration; then the rats chose between two levers. The rewarded choice depended on the duration of the stimulus. On conditioning trials, the stimulus used on choice trials was presented, but it ended without food (extinction trials) or with food (pairing trials) regardless of what the rat did. The main stimulus minus accuracy with the long stimulus. Experiment 1 showed that extinction trials increased short bias relative to training without conditioning trials or to training with pairing trials. The rest of the experiments tested explanations of these results. The same results were found when extinction trials were the same duration as the short stimulus (Experiment 2), when extinction trials were a random duration (Experiment 5), and when the signal value of the conditioned stimulus was changed in another way (Experiment 6). The effect of conditioning trials was modality specific (Experiments 3 and 4). Of the explanations considered, the best one--the only one not contradicted at least once--is that changing the signal value of a stimulus changes how the clock times the stimulus. Reducing signal value reduces the measured duration.  相似文献   
900.
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   
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