全文获取类型
收费全文 | 40815篇 |
免费 | 1333篇 |
国内免费 | 8篇 |
出版年
2019年 | 432篇 |
2018年 | 1883篇 |
2017年 | 1761篇 |
2016年 | 1443篇 |
2015年 | 451篇 |
2014年 | 532篇 |
2013年 | 2375篇 |
2012年 | 1199篇 |
2011年 | 2001篇 |
2010年 | 1620篇 |
2009年 | 1169篇 |
2008年 | 1635篇 |
2007年 | 1838篇 |
2006年 | 836篇 |
2005年 | 831篇 |
2004年 | 786篇 |
2003年 | 695篇 |
2002年 | 714篇 |
2001年 | 1032篇 |
2000年 | 950篇 |
1999年 | 714篇 |
1998年 | 385篇 |
1997年 | 313篇 |
1996年 | 310篇 |
1992年 | 548篇 |
1991年 | 541篇 |
1990年 | 530篇 |
1989年 | 537篇 |
1988年 | 530篇 |
1987年 | 494篇 |
1986年 | 521篇 |
1985年 | 570篇 |
1984年 | 451篇 |
1983年 | 431篇 |
1982年 | 354篇 |
1981年 | 337篇 |
1979年 | 521篇 |
1978年 | 378篇 |
1977年 | 311篇 |
1976年 | 359篇 |
1975年 | 432篇 |
1974年 | 486篇 |
1973年 | 507篇 |
1972年 | 407篇 |
1971年 | 381篇 |
1970年 | 378篇 |
1969年 | 408篇 |
1968年 | 488篇 |
1967年 | 421篇 |
1966年 | 422篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
231.
Psychophysical studies with infants or with patients often are unable to use pilot data, training, or large numbers of trials. To evaluate threshold estimates under these conditions, computer simulations of experiments with small numbers of trials were performed by using psychometric functions based on a model of two types of noise: stimulus-related noise (affecting slope) and extraneous noise (affecting upper asymptote). Threshold estimates were biased and imprecise when extraneous noise was high, as were the estimates of extraneous noise. Strategies were developed for rejecting data sets as too noisy for unbiased and precise threshold estimation; these strategies were most successful when extraneous noise was low for most of the data sets. An analysis of 1,026 data sets from visual function tests of infants and toddlers showed that extraneous noise is often considerable, that experimental paradigms can be developed that minimize extraneous noise, and that data analysis that does not consider the effects of extraneous noise may underestimate test-retest reliability and overestimate interocular differences. 相似文献
232.
A soft contact-lens system for achieving unilateral visual stimulation in a free vision format is described. Initial testing with light transmittance and visual perimetry indicated that the lenses created artificial visual-field deficits. The efficacy of the lenses as a technique for lateralizing visual input was evaluated by examining within-subject differences in performance on two visuospatial tasks. Speed and accuracy of performance were greater with visual input directed to the right hemisphere. These data support the lens design as a useful alternative to tachistoscopic procedures and previous lens systems. 相似文献
233.
The Profile of Mood States was printed on four different colors of paper (yellow, red, green, blue) and white to test whether the color of paper would influence mood state scores of 246 college students. Univariate analyses of variance identified color effects only on the Fatigue scale. 相似文献
234.
Item recognition requires discrimination of studied words from nonstudied words. Associative recognition requires subjects to discriminate studied word groups from recombinations of words from different groups. Cued recognition requires the same old-new discrimination as item recognition, but list items are presented as cues along with the test item. The results from three experiments show (1) little or no effect of cuing for low-frequency words, but (2) positive cuing effects for high-frequency words; (3) increasing levels of overall performance with increases in study time, but (4) unchanging effects of cuing with study time; and (5) stronger positive cuing effects for two cues than for one cue. Five models (Independent Cue Model, Matrix model, MINERVA 2, SAM, and TODAM) were fit to the data of Experiment 1. Each model has trouble with at least one aspect of the results. Theoretical implications and modifications are discussed at length. 相似文献
235.
Dr. Alastair J. Flint Sandra E. Black Irene Campbell-Taylor Gillian F. Gailey Carey Levinton 《Journal of psycholinguistic research》1992,21(5):383-399
In its early stages, Parkinson's disease (P.D.) may be difficult to distinguish from major depression (M.D.) leading to inappropriate management. Both illnesses are characterized by psychomotor retardation. The neurovegetative symptoms used to diagnose M.D. are not specific and in P.D. may be due to the physical illness itself. Currently, differentiation of the two disorders relies on subjective clinical observation. Improved diagnostic accuracy based on more objective data is needed. To this end, this study used computerized acoustic analysis to contrast speech patterns in P.D. and M.D. The sample consisted of 30 P.D. patients without depression or dementia, 30 patients with uncomplicated M.D., and 31 normal controls, each 60 years of age or over. Of the acoustic variables studied, M.D. patients had significantly reduced rates of speech compared with P.D. patients. The data suggest that this temporal measure of speech may be useful in the differentiation of P.D. and M.D. 相似文献
236.
Musical duplex perception: perception of figurally good chords with subliminal distinguishing tones.
M D Hall R E Pastore 《Journal of experimental psychology. Human perception and performance》1992,18(3):752-762
In a variant of duplex perception with speech, phoneme perception is maintained when distinguishing components are presented below intensities required for separate detection, forming the basis for the claim that a phonetic module takes precedence over nonspeech processing. This finding is replicated with music chords (C major and minor) created by mixing a piano fifth with a sinusoidal distinguishing tone (E or E flat). Individual threshold intensities for detecting E or E flat in the context of the fixed piano tones are established. Chord discrimination thresholds defined by distinguishing tone intensity were determined. Experiment 2 verified masked detection thresholds and subliminal chord identification for experienced musicians. Accurate chord perception was maintained at distinguishing tone intensities nearly 20 dB below the threshold for separate detection. Speech and music findings are argued to demonstrate general perceptual principles. 相似文献
237.
Temporary suppression of visual processing in an RSVP task: an attentional blink? . 总被引:37,自引:0,他引:37
J E Raymond K L Shapiro K M Arnell 《Journal of experimental psychology. Human perception and performance》1992,18(3):849-860
Through rapid serial visual presentation (RSVP), we asked Ss to identify a partially specified letter (target) and then to detect the presence or absence of a fully specified letter (probe). Whereas targets are accurately identified, probes are poorly detected when they are presented during a 270-ms interval beginning 180 ms after the target. Probes presented immediately after the target or later in the RSVP stream are accurately detected. This temporary reduction in probe detection was not found in conditions in which a brief blank interval followed the target or Ss were not required to identify the target. The data suggest that the presentation of stimuli after the target but before target-identification processes are complete produces interference at a letter-recognition stage. This interference may cause the temporary suppression of visual attention mechanisms observed in the present study. 相似文献
238.
On the transmission of partial information: inferences from movement-related brain potentials. 总被引:1,自引:0,他引:1
A Osman T R Bashore M G Coles E Donchin D E Meyer 《Journal of experimental psychology. Human perception and performance》1992,18(1):217-232
Results are reported from a new paradigm that uses movement-related brain potentials to detect response preparation based on partial information. The paradigm uses a hybrid choice-reaction go/nogo procedure in which decisions about response hand and whether to respond are based on separate stimulus attributes. A lateral asymmetry in the movement-related brain potential was found on nogo trials without overt movement. The direction of this asymmetry depended primarily on the signaled response hand rather than on properties of the stimulus. When the asymmetry first appeared was influenced by the time required to select the signaled hand, and when it began to differ on go and nogo trials was influenced by the time to decide whether to respond. These findings indicate that both stimulus attributes were processed in parallel and that the asymmetry reflected preparation of the response hand that began before the go/nogo decision was completed. 相似文献
239.
240.
There is evidence of two major components of grammatic function in the brain: (1) morphologic, probably based in the postcentral perisylvian cortex, encompassing the selection of individual words and inflectional endings according to the rules of grammar; and (2) syntactic, probably based in the frontal lobes, encompassing construction of the overall structure of a sentence (syntax) to match the concept being considered. We present a stroke patient with impaired morphology but, unlike Broca's aphasics, relative sparing of syntax. He omitted 43% of articles, 40% of complementizers, 20% of pronouns, 27% of semantically marked prepositions, 43% of purely grammatic prepositions, and 22% of auxiliary verbs, but his average sentence length was 9.8 words and 64% of his sentences contained embedded clauses. He frequently intermingled two sentences to convey a given concept, juxtaposing words in grammatically unacceptable ways. This intermingling may represent either a grammatic "conduite d'approche," or a failure of the filtering function of a defective morphologic processor. His great difficulty in completing syntactic frames suggests that a more general form of the processes underlying grammatic morphology may play an important role in phrase structure generation. 相似文献