全文获取类型
收费全文 | 54413篇 |
免费 | 1568篇 |
国内免费 | 29篇 |
专业分类
56010篇 |
出版年
2021年 | 315篇 |
2020年 | 465篇 |
2019年 | 536篇 |
2018年 | 4020篇 |
2017年 | 3354篇 |
2016年 | 2914篇 |
2015年 | 728篇 |
2014年 | 735篇 |
2013年 | 3083篇 |
2012年 | 1857篇 |
2011年 | 3520篇 |
2010年 | 3154篇 |
2009年 | 2186篇 |
2008年 | 2682篇 |
2007年 | 3093篇 |
2006年 | 973篇 |
2005年 | 1034篇 |
2004年 | 902篇 |
2003年 | 810篇 |
2002年 | 779篇 |
2001年 | 1120篇 |
2000年 | 1164篇 |
1999年 | 820篇 |
1998年 | 362篇 |
1997年 | 330篇 |
1995年 | 326篇 |
1992年 | 652篇 |
1991年 | 600篇 |
1990年 | 591篇 |
1989年 | 559篇 |
1988年 | 559篇 |
1987年 | 493篇 |
1986年 | 488篇 |
1985年 | 537篇 |
1984年 | 447篇 |
1983年 | 409篇 |
1982年 | 314篇 |
1979年 | 486篇 |
1978年 | 338篇 |
1976年 | 330篇 |
1975年 | 366篇 |
1974年 | 442篇 |
1973年 | 469篇 |
1972年 | 407篇 |
1971年 | 351篇 |
1970年 | 326篇 |
1969年 | 344篇 |
1968年 | 426篇 |
1967年 | 378篇 |
1966年 | 364篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
921.
L Isenberg M J Nissen L C Marchak 《Journal of experimental psychology. Human perception and performance》1990,16(4):869-878
Judgments of the color and shape of a stimulus specified by a cue indicating its location demonstrate stochastic independence. Evidence for the independence of color and orientation was obtained when the cue followed stimulus offset immediately, the cue followed stimulus offset by 2 s, and when either a central or peripheral precue focused attention on the cued stimulus at the time of its presentation. It appears that an object's color and orientation are represented independently even following the attentional focusing thought to support feature integration. 相似文献
922.
J C Baird M Wagner K Fuld 《Journal of experimental psychology. Human perception and performance》1990,16(3):675-677
Modification of Restle's theory (1970) explains the moon illusion and related phenomena on the basis of three principles: (1) The apparent sizes of objects are their perceived visual angles. (2) The apparent size of the moon is determined by the ratio of the angular extent of the moon relative to the extents subtended by objects composing the surrounding context, such as the sky and things on the ground. (3) The visual extents subtended by common objects of a constant physical size decrease systematically with increasing distance from the observer. Further development of this theory requires specification of both the components of the surrounding context and their relative importance in determining the apparent size and distance of the moon. 相似文献
923.
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
924.
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
925.
926.
927.
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
928.
R. Harré 《国际科学哲学研究》1990,4(2):149-158
How is meaning assigned to those terms in a theory which are remote from direct observational instantiation? Models and analogies play a role, but close examination of theories in high energy physics shows that the design of experimental apparatus also influences the interpretation of such terms. Certain apparatus favours certain kinds of effects, and this affects the way mathematical theories are interpreted. In particular track producing apparatus becomes involved with theories in which photonic terms are picked out in the theory. A further conceptual constraint is thus introduced. It is argued that this situation favours the interpretation of dispositional properties as affordances rather than as simple dispositions. 相似文献
929.
Mart Fehér 《国际科学哲学研究》1990,4(3):229-240
The role accorded to the public by scientists and philosophers of science has undergone an essential historical change in the last three centuries. Public participation in (witnessing of) scientific experiments was considered an important requirement for 17th century experimenters (e.g. for Boyle or Pascal). The cognitive role played by lay persons was later substantially downgraded; witnessing went out of fashion, while science became more and more esoteric and a matter for experts only. Part of this process was that all scientific disciplines became intensively compartmentalized and in consequence a rather puzzling or even paradoxical situation appeared: that the scientists themselves were and are being reduced epistemically to the status of lay persons, outside of their proper field of expertise (as was pointed out by J. Hardwig). The paper deals with some cognitive aspects of this historical process. 相似文献
930.
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