全文获取类型
收费全文 | 38512篇 |
免费 | 1625篇 |
国内免费 | 26篇 |
专业分类
40163篇 |
出版年
2020年 | 428篇 |
2019年 | 549篇 |
2018年 | 741篇 |
2017年 | 745篇 |
2016年 | 847篇 |
2015年 | 571篇 |
2014年 | 708篇 |
2013年 | 3236篇 |
2012年 | 1269篇 |
2011年 | 1276篇 |
2010年 | 788篇 |
2009年 | 853篇 |
2008年 | 1116篇 |
2007年 | 1112篇 |
2006年 | 998篇 |
2005年 | 885篇 |
2004年 | 882篇 |
2003年 | 798篇 |
2002年 | 876篇 |
2001年 | 1144篇 |
2000年 | 1136篇 |
1999年 | 887篇 |
1998年 | 443篇 |
1997年 | 410篇 |
1995年 | 421篇 |
1993年 | 384篇 |
1992年 | 721篇 |
1991年 | 672篇 |
1990年 | 639篇 |
1989年 | 616篇 |
1988年 | 597篇 |
1987年 | 537篇 |
1986年 | 543篇 |
1985年 | 608篇 |
1984年 | 523篇 |
1983年 | 505篇 |
1982年 | 409篇 |
1981年 | 385篇 |
1979年 | 581篇 |
1978年 | 437篇 |
1977年 | 409篇 |
1976年 | 406篇 |
1975年 | 454篇 |
1974年 | 531篇 |
1973年 | 521篇 |
1972年 | 455篇 |
1969年 | 382篇 |
1968年 | 455篇 |
1967年 | 404篇 |
1966年 | 388篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
891.
In category classification tasks, typicality effects are usually found: accuracy and reaction time depend upon distance from a prototype. In this study, subjects learned either verbal or nonverbal dot pattern categories, followed by a lateralized classification task. Comparable typicality effects were found in both reaction time and accuracy across visual fields for both verbal and nonverbal categories. Both hemispheres appeared to use a similarity-to-prototype matching strategy in classification. This indicates that merely having a verbal label does not differentiate classification in the two hemispheres. 相似文献
892.
Ethanol-mediated taste aversions and state-dependency in preweanling (16-day-old) rats 总被引:1,自引:0,他引:1
Requirements for conditioning of an ethanol-mediated taste aversion in 16-day-old rat pups were examined. Experiment 1 demonstrated that preweanling rats are capable of acquiring, in two trials, an aversion to a 15% sucrose solution when followed by intragastric intubation of a 1.2 g/kg dose of 17% v/v ethanol, but not when followed by a 0.4 g/kg dose. Comparison was with control animals given sucrose followed by an equivalent volume isocaloric Half and Half. When the 0.4 g/kg dose of ethanol preceded sucrose presentation by 30 min (Experiment 2), the aversion was learned, suggesting that the effective delay between the sucrose and the critical consequences of the ethanol had been too long with the former procedure. Expression of the sucrose aversion required, however, the reinstatement of the context of intoxication--state-dependent retention. Finally, the results of Experiment 3B indicated that, in addition to the association between the sucrose and the aversive consequences of alcohol intoxication, the orosensory cues resulting from alcohol's direct elimination, via such processes as respiration and salivation, became associated with the appetitive properties of the sucrose. This was evidenced by a conditioned increase in preference for ethanol odor. Possible age-related differences in the ability to associate stimuli with alcohol's unconditioned consequences, and in state dependency are discussed. 相似文献
893.
894.
It has been suggested that family satisfaction can be measured by having a person complete the Family Adaptability and Cohesion Evaluation Scale (FACES-II) twice: once as the person essentially sees the family (actual version), and once as they wish the family to be (ideal version). The discrepancy between the actual and ideal scores is contended to be a measure of satisfaction with family. Though conceptually attractive, this measurement strategy was not verified, as assessed in the present study by correlating the actual-ideal discrepancy scores with family discord (Index of Family Relations) scores. Clinical adoption of the actual-ideal discrepancy-score as a measure of family satisfaction is thus seen as premature, until more supportive evidence is demonstrated. 相似文献
895.
James M. Edie 《Human Studies》1990,13(2):103-118
This paper was presented as the Aaron Gurwitsch Memorial Lecture, sponsored by the Center for Advanced Research in Phenomenology, Inc., at Northwestern University, Evanston, Illinois, October 1988. 相似文献
896.
897.
James M. Dabbs Jr Charles H. Hopper Gregory J. Jurkovic 《Personality and individual differences》1990,11(12)
Relationships of serum and saliva to personality were examined among 401 college students in four laboratory studies and 5,236 military veterans in one archival study. Among the students, there were few relationships between testosterone and traditional personality measures. Among the veterans, MMPI scores and DSM-III diagnoses showed testosterone related to drug and alcohol abuse, antisocial and generally intemperate behavior, and effective disorders. Consistent with social control theory, correlations were higher among veterans who were lower in socioeconomic status. It appears likely that testosterone has innate effects that are socially undesirable but can be attenuated by bonds between the individual and society. Effect sizes were small, suggesting that testosterone will have noticeable effects only in large populations or individuals who differ markedly from the population mean. Further research should focus upon antisocial correlates of testosterone and conditions that produce marked changes in testosterone levels. 相似文献
898.
Event-Related Potentials were recorded over occipital and parietal scalp from left- and right-handed adults presented with a language and a non-language visual stimulus using a divided field, "oddball" paradigm. The major finding of interest was that the P300 component was larger over the left than the right hemisphere of the right-handers when the language stimulus was presented to the left hemisphere; there were no hemispheric differences for the left-handers, regardless of field of presentation. These results are discussed in the context of developing noninvasive measures to lateralize language function. 相似文献
899.
James Robert Brown 《国际科学哲学研究》1990,4(2):117-130
Proofs and Refutations is Lakatos's masterpiece. This article investigates some of its central themes, in particular: the nature of proofs ('Proofs do not prove, they improve'); the nature of definitions (real, not nominal); and the consequences of all this for ontology (platonism vs Popper's World Three). 相似文献
900.
Long-term effects of cerebellar pathology on cognitive functions 总被引:3,自引:0,他引:3
Twelve patients with circumscribed chronic neocerebellar lesions but without CT-evidence of forebrain damage (other than the effects of shunting) were investigated for deficits of cognitive functions. Two different mechanisms were considered as possible causes of cognitive impairment: (1) Damage to the dentato-thalamo-cortical projection leading to impairments of cortical functions, and (2) prolonged intracranial pressure resulting in diffuse forebrain damage and subcortical dementia. Patients with lesions in the left neocerebellum showed deficits in cognitive operations in three dimensional space, consistent with the right forebrain dominance for spatial functions. Prolonged intracranial pressure, on the other hand, resulted in a mild overall cognitive impairment. 相似文献