全文获取类型
收费全文 | 50938篇 |
免费 | 1033篇 |
国内免费 | 6篇 |
专业分类
51977篇 |
出版年
2020年 | 571篇 |
2019年 | 650篇 |
2018年 | 861篇 |
2017年 | 862篇 |
2016年 | 987篇 |
2015年 | 719篇 |
2014年 | 865篇 |
2013年 | 3801篇 |
2012年 | 1584篇 |
2011年 | 1553篇 |
2010年 | 1049篇 |
2009年 | 1014篇 |
2008年 | 1455篇 |
2007年 | 1435篇 |
2006年 | 1256篇 |
2005年 | 1154篇 |
2004年 | 1151篇 |
2003年 | 1044篇 |
2002年 | 1061篇 |
2001年 | 1436篇 |
2000年 | 1403篇 |
1999年 | 1058篇 |
1998年 | 570篇 |
1997年 | 487篇 |
1992年 | 975篇 |
1991年 | 908篇 |
1990年 | 919篇 |
1989年 | 814篇 |
1988年 | 809篇 |
1987年 | 782篇 |
1986年 | 793篇 |
1985年 | 882篇 |
1984年 | 698篇 |
1983年 | 635篇 |
1982年 | 469篇 |
1981年 | 475篇 |
1979年 | 784篇 |
1978年 | 523篇 |
1977年 | 497篇 |
1976年 | 498篇 |
1975年 | 642篇 |
1974年 | 740篇 |
1973年 | 767篇 |
1972年 | 653篇 |
1971年 | 619篇 |
1970年 | 587篇 |
1969年 | 578篇 |
1968年 | 769篇 |
1967年 | 675篇 |
1966年 | 598篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
241.
Intellectual functioning and aggression 总被引:2,自引:0,他引:2
In a 22-year study, data were collected on aggressiveness and intellectual functioning in more than 600 subjects, their parents, and their children. Both aggression and intellectual functioning are reasonably stable in a subject's lifetime and perpetuate themselves across generations and within marriage pairs. Aggression in childhood was shown to interfere with the development of intellectual functioning and to be predictive of poorer intellectual achievement as an adult. Early IQ was related to early subject aggression but did not predict changes in aggression after age 8. On the other hand, differences between early IQ and intellectual achievement in middle adulthood were predictable from early aggressive behavior. A dual-process model was offered to explain the relation between intellectual functioning and aggressive behavior. We hypothesized that low intelligence makes the learning of aggressive responses more likely at an early age, and this aggressive behavior makes continued intellectual development more difficult. 相似文献
242.
243.
Lonnie R. Snowden 《American journal of community psychology》1987,15(5):575-586
The 20-year history of community psychology is considered with respect to activities on behalf of ethnic minority participation in psychotherapy, increasing cultural diversity, and to a considerably lesser extent, enhancing community systems. A discrepancy was found between community psychology in principle and community psychology in practice. For the future, community psychologists are advised to identify and seek to strengthen (a) indigenous resources for solving personal and community problems; and (b) pathways of help seeking followed by community members. Community psychology is encouraged to reclaim and enact more vigorously its own legacy. To do otherwise, it is argued, forfeits development of potentially significant research and practice and risks continued ambivalence and dissatisfaction despite worthwhile contribution--suffering the peculiar successes of community psychology. 相似文献
244.
Two studies are reported which examine the availability of scientific propositions of personality in lay conceptions of personality. It is argued from a social constructivist perspective that models of personality must derive from and refer to lay conceptions of persons. Eysenck's trait-type model of introversion-extraversion, containing specific propositions about phenotypic and genotypic differences between extraverts and introverts, was utilized as the scientific model of personality and its availability in lay conceptions of personality was examined in two studies. In the first study, subjects were presented with a genotypic characterization of either an introvert or an extravert target person and asked to infer corresponding phenotypic differences. In the second study, the inference process was reversed with subjects being asked to infer genotypic characteristics of introverts versus extraverts on the basis of phenotypic target person desecrations of the two types. Results from both studies show a high degree of accuracy in subjects' inferences, suggesting that laypersons have well-formed conceptions about personality containing ‘higher-order’ psychogenetic propositions corresponding to Eysenck's trait-type model. The implications of the findings for theory construction are discussed. 相似文献
245.
Regional cerebral blood flow (rCBF) may be measured with inhalation techniques that use end-expired values of radioactivity to estimate the isotope concentration in arterial blood. These end-expired data are used as an input function in a mathematical equation to derive rCBF. End-expired air is assumed normally to be in equilibrium with the arterial blood at the alveolar surface of the lung during regular (passive) breathing; this assumption may not be valid during continuous phonation. We therefore have analyzed breathing (inhalation/exhalation) patterns and end-expired radioactivity (133Xe) during (1) speaking, (2) singing, and (3) humming of the national anthem, and also during (4) passive breathing. Statistically significant differences in breathing patterns were measured between a group of nonmusicians and two groups of musicians (singers) during the phonation tasks: The nonmusicians breathed more often (and more rapidly) and exhibited less variability in their breathing patterns than did the musicians. Notwithstanding these differences, the shapes of smoothed functions derived from the end-expired values were not influenced appreciably during phonation (except possibly during talking). The latter finding suggests that estimates of rCBF derived with these data should not be confounded seriously because of the continuous phonation. 相似文献
246.
Douglas Cullinan Kenneth D. Gadow Michael H. Epstein 《Journal of abnormal child psychology》1987,15(4):469-477
Psychotropic drug treatment in learning-disabled (LD), educable mentally retarded (EMR), and seriously emotionally disturbed (ED) children and adolescents receiving public school special education services was examined. The findings indicated that while treatment prevalence rates for EMR and ED groups were comparable, the rate for LD students was much lower. In the LD sample, pharmacotherapy was associated with higher ratings of behavioral deviance, longer placement in special education, less social integration, and greater peer rejection, which suggests that symptom severity is an important determiner of pharmacotherapy in this population. 相似文献
247.
The interactional teaching strategies of mothers and fathers toward their sociometrically determined popular, moderately popular, or unpopular children, and children's responses to them were examined during a structured puzzle task in a laboratory setting. Parents of popular children used more explanations in aiding their children to complete the puzzle task than parents of moderately popular or unpopular children. Mothers were more likely to offer suggestions, use explanations, and ask questions during the puzzle task than fathers. Analysis of children's responses revealed that popular children were more likely to ignore imperatives by their parents compared with unpopular children, while unpopular children showed a tendency to be more cooperative following imperatives by parents than popular children. Finally, popular children were less likely to ignore but were more likely to go off task following suggestions by parents than either unpopular or moderately popular children. The data are discussed with respect to the possible link between parental socialization patterns and children's popularity in the peer group and the need to consider the interaction patterns in both the peer and parent-child systems for intervention purposes.Portions of this paper were presented by the first author at the Banff International Conference on Behavioral Science, Banff, Alberta, Canada, 1984. The research was supported through the Western Regional Project W144, Development of Social Competencies in Children, with funding from Science and Education Administration/Cooperative Research of the USDA and Utah State University Agricultural Experiment Station. We would like to thank the parents and children for their participation, and Nina Mounts, Maria Norton, Carla Seamons, Soheila Sobhani, and Joan Wareham for their assistance with varying aspects of coding and data analysis. 相似文献
248.
The functional development of cardiac and adrenal medullary responses to reflex activation of the sympathetic nervous system was studied in preweanling spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) normotensive rats. Pups of the two strains received injections of insulin or saline at 2, 4, 8, 12, or 16 days of age and were sacrificed 3 h later. Insulin administration produces a significant decrease in circulating levels of glucose which in turn results in a centrally mediated increase in sympathetic outflow. The induction of ornithine decarboxylase (ODC) in heart and the depletion of epinephrine from the adrenal medulla served as tissue markers of functional sympathetic neurotransmission. WKY and SHR pups had comparable levels of ODC activity in heart under basal conditions. In contrast, levels of catecholamines in the adrenals were greater in SHR pups at 2 and 4 days of age. Following insulin administration, SHR pups exhibited a greater induction of cardiac ODC activity at 2, 4, and 8 days of age compared to age-matched WKY controls. However, there were no differences between SHR and WKY pups in the magnitude of the adrenal medullary response to insulin-induced hypoglycemia. These alterations in sympathetic-target tissue development during the first postnatal week of life may contribute in part to the higher arterial pressures maintained by SHRs throughout the lifespan. 相似文献
249.
A long-term temporal component of working memory of rats trained on the radial maze has been shown to be susceptible to disruption by the protein synthesis inhibitor, anisomycin. It is not clear whether protein synthesis played a role in working memory because accurate performance on the radial maze required the storage of a large amount of information, or because the information was to be held in store for relatively long periods of time. This experiment tested these hypotheses by assessing the effect of anisomycin on choice accuracy in a comparatively simple spatial delayed alternation task. Results indicate that under the present training conditions, protein involvement in working memory is related more to the length of the retention interval than to the amount of information retained. 相似文献
250.
When day-old chicks are trained on a passive avoidance task there is enhanced synthesis of glycoproteins. Bilateral intracerebral injections of 20 mumole of 2-deoxygalactose (2-D-gal), administered just before and just after training on the task, produce amnesia for the avoidance. Amnesia develops slowly over the first hour and persists for at least 24 h subsequently. If 2-D-gal injections are administered 4 h prior to the training or delayed for 3 h after training, no amnesia occurs. Apart from a brief initial suppression of pecking following injection there are no effects of 2-D-gal on other observed behaviors of the birds. Within the first hour this dose of 2-D-gal inhibits [3H]fucose incorporation into acid-insoluble material by 26% (or 68%, calculated relative to free pool fucose). The amnestic effect of 2-D-gal is not shown by galactose, glucose, fucose, or 2-D-glucose. Injecting 40 mumole of galactose simultaneously with the 2-D-gal abolishes the 2-D-gal-induced amnesia; 40 mumole of fucose, however, does not abolish the amnesia. The utility of 2-D-gal as an agent for analyzing the role of glycoproteins in memory formation is discussed. 相似文献