全文获取类型
收费全文 | 178528篇 |
免费 | 7959篇 |
国内免费 | 156篇 |
专业分类
186643篇 |
出版年
2020年 | 2781篇 |
2019年 | 3425篇 |
2018年 | 3491篇 |
2017年 | 3949篇 |
2016年 | 4585篇 |
2015年 | 3910篇 |
2014年 | 4788篇 |
2013年 | 23407篇 |
2012年 | 4614篇 |
2011年 | 3665篇 |
2010年 | 3851篇 |
2009年 | 4746篇 |
2008年 | 3890篇 |
2007年 | 3422篇 |
2006年 | 4029篇 |
2005年 | 4030篇 |
2004年 | 3507篇 |
2003年 | 3138篇 |
2002年 | 2944篇 |
2001年 | 3538篇 |
2000年 | 3389篇 |
1999年 | 3299篇 |
1998年 | 2837篇 |
1997年 | 2669篇 |
1996年 | 2597篇 |
1995年 | 2425篇 |
1994年 | 2391篇 |
1993年 | 2355篇 |
1992年 | 2808篇 |
1991年 | 2642篇 |
1990年 | 2520篇 |
1989年 | 2381篇 |
1988年 | 2349篇 |
1987年 | 2381篇 |
1986年 | 2369篇 |
1985年 | 2629篇 |
1984年 | 2636篇 |
1983年 | 2414篇 |
1982年 | 2400篇 |
1981年 | 2379篇 |
1980年 | 2196篇 |
1979年 | 2363篇 |
1978年 | 2232篇 |
1977年 | 2195篇 |
1976年 | 2016篇 |
1975年 | 2164篇 |
1974年 | 2246篇 |
1973年 | 2153篇 |
1972年 | 1734篇 |
1971年 | 1658篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
851.
Tests of central auditory function and measures of receptive and expressive language abilities were administered to 10 children suspected of having central auditory processing disorders. Eight of the 10 subjects displayed expressive language difficulties, suggesting a need to examine more closely the relationship between expressive language and central auditory processing. 相似文献
852.
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
853.
P Tassi A Nicolas G Dewasmes R Eschenlauer J Ehrhart P Salame A Muzet J P Libert 《Perceptual and motor skills》1992,75(1):291-302
The purpose of the present study was to analyse the arousing effects of noise on sleep inertia as a function of circadian placement of a one-hour nap. In a first experiment, we measured the effects of sleep inertia in a neutral acoustic environment after a one-hour nap placed either at 0100 or 0400 on response time during a spatial memory test. In a second experiment were analysed the effects of an intense continuous noise on sleep inertia. The results showed that noise produced a total abolition of sleep inertia after an early nap (0000 to 0100). This may be due to the arousing effect of noise; however, results are less clear after a late nap 0300 to 0400 as noise seems to be ineffective. This result is discussed in terms of either a function of time-of-day effect or of prior sleep intensity. Moreover, our data suggest a possible interaction of noise with partial sleep deprivation leading to a slight deleterious effect those subjects who did not sleep at all. 相似文献
854.
This paper suggests a method to supplant missing categorical data by reasonable replacements. These replacements will maximize the consistency of the completed data as measured by Guttman's squared correlation ratio. The text outlines a solution of the optimization problem, describes relationships with the relevant psychometric theory, and studies some properties of the method in detail. The main result is that the average correlation should be at least 0.50 before the method becomes practical. At that point, the technique gives reasonable results up to 10–15% missing data.We thank Anneke Bloemhoff of NIPG-TNO for compiling and making the Dutch Life Style Survey data available to use, and Chantal Houée and Thérèse Bardaine, IUT, Vannes, France, exchange students under the COMETT program of the EC, for computational assistance. We also thank Donald Rubin, the Editors and several anonymous reviewers for constructive suggestions. 相似文献
855.
856.
857.
Deborah G. Mayo 《Synthese》1992,90(2):233-262
I document some of the main evidence showing that E. S. Pearson rejected the key features of the behavioral-decision philosophy that became associated with the Neyman-Pearson Theory of statistics (NPT). I argue that NPT principles arose not out of behavioral aims, where the concern is solely with behaving correctly sufficiently often in some long run, but out of the epistemological aim of learning about causes of experimental results (e.g., distinguishing genuine from spurious effects). The view Pearson did hold gives a deeper understanding of NPT tests than their typical formulation as accept-reject routines, against which criticisms of NPT are really directed. The Pearsonian view that emerges suggests how NPT tests may avoid these criticisms while still retaining what is central to these methods: the control of error probabilities.A portion of this research was carried out during tenure of a National Endowment for the Humanities Summer Stipend Fellowship; I gratefully acknowledge that support. A version of this paper was presented at the 1987 meeting of the Society for Exact Philosophy. This paper benefited from discussions and communications with George Barnard and Isaac Levi. I thank Harlan Miller for helpful comments on earlier drafts. 相似文献
858.
Binary programming models are presented to generate parallel tests from an itembank. The parallel tests are created to match item for item an existing seed test and match user supplied taxonomic specifications. The taxonomic specifications may be either obtained from the seed test or from some other user requirement. An algorithm is presented along with computational results to indicate the overall efficiency of the process. Empirical findings based on an itembank for the Arithmetic Reasoning section of the Armed Services Vocational Aptitude Battery are given.The Office of Naval Research, Program in Cognitive Science, N00014-87-C-0696 partially supported the work of Douglas H. Jones. The Rutgers Research Resource Committee of the Graduate School of Management partially supported the work of Douglas H. Jones and Ing-Long Wu. A Thomas and Betts research fellowship partially supported the work of Ing-Long Wu. The Human Resources Laboratory, United States Air Force, partially supported the work of Ronald Armstrong. The authors benefited from conversations with Dr. Wayne Shore, Operational Technologies, San Antonio, Texas. The order of authors' names is alphabetical and denotes equal authorship. 相似文献
859.
O Neumann R Koch M Niepel T Tappe 《Zeitschrift für experimentelle und angewandte Psychologie》1992,39(4):621-645
Dissociations between a motor response and the subject's verbal report have been reported from various experiments that investigated special experimental effects (e.g., metacontrast or induced motion). To examine whether similar dissociations can also be observed under standard experimental conditions, we compared reaction times (RT) and temporal order judgments (TOJ) to visual and auditory stimuli of three intensity levels. Data were collected from six subjects, each of which served for nine sessions. The results showed a strong, highly significant modality dissociation: While RTs to auditory stimuli were shorter than RTs to visual stimuli, the TOJ data indicated longer processing times for auditory than for visual stimuli. This pattern was found over the whole range of intensities investigated. Light intensity had similar effects on RT and TOJ, while there was a marginally significant tendency of tone intensity to affect RT more strongly than TOJ. It is concluded that modality dissociation is an example of "direct parameter specification", where the pathway from stimulus to response in the simple RT experiment is (at least partially) separate from the pathway that leads to a conscious, reportable representation. Two variants of this notion and alternatives to it are discussed. 相似文献
860.
R B?sel 《Zeitschrift für experimentelle und angewandte Psychologie》1992,39(3):372-395
Based on previous findings (B?sel et al., 1990) it was assumed that in concept learning tasks generating on hypotheses on a concept which has to be developed is accompanied by increases of the Alpha 1 power (7.5-10 Hz) in the spontaneous EEG activity. In this study 16 subjects performed five problem solving tasks with similar processing requirements. EEG data were analyzed by means of post hoc comparisons of subjects differing in performance quality. Additionally, four control tasks were employed in which, based on previous studies, variations in the Theta frequency range were expected. An effect in the Alpha 1 frequency band was observed in tasks requiring reconstructive recall or testing the usefulness of an mathematical algorithm. The creation of a rank order or mental map is accompanied by power increases in the lower portions of the Alpha 1 frequency band (7.5-8.5 Hz). Moreover a high amount of controlled variance (eta2 up to 34%) was obtained for this effect. Increases in EEG Theta power, which presumably indicate subjects' component analysis, were found before the subjects recognized parts of geometric figures or before relevant features in the "buddhist monk problem" were discriminated. The dynamics of EEG power over time is in examples of frequency/time plots in a figure, illustrated. 相似文献