全文获取类型
收费全文 | 48079篇 |
免费 | 1904篇 |
国内免费 | 22篇 |
专业分类
50005篇 |
出版年
2020年 | 620篇 |
2019年 | 764篇 |
2018年 | 1024篇 |
2017年 | 1067篇 |
2016年 | 1137篇 |
2015年 | 771篇 |
2014年 | 977篇 |
2013年 | 4095篇 |
2012年 | 1728篇 |
2011年 | 1729篇 |
2010年 | 1160篇 |
2009年 | 1137篇 |
2008年 | 1632篇 |
2007年 | 1636篇 |
2006年 | 1447篇 |
2005年 | 1272篇 |
2004年 | 1267篇 |
2003年 | 1180篇 |
2002年 | 1168篇 |
2001年 | 1323篇 |
2000年 | 1286篇 |
1999年 | 1031篇 |
1998年 | 550篇 |
1997年 | 514篇 |
1996年 | 436篇 |
1995年 | 484篇 |
1994年 | 471篇 |
1993年 | 459篇 |
1992年 | 849篇 |
1991年 | 740篇 |
1990年 | 793篇 |
1989年 | 699篇 |
1988年 | 737篇 |
1987年 | 690篇 |
1986年 | 680篇 |
1985年 | 634篇 |
1984年 | 607篇 |
1983年 | 563篇 |
1982年 | 444篇 |
1981年 | 432篇 |
1980年 | 427篇 |
1979年 | 656篇 |
1978年 | 492篇 |
1975年 | 509篇 |
1974年 | 563篇 |
1973年 | 578篇 |
1972年 | 425篇 |
1971年 | 421篇 |
1968年 | 486篇 |
1967年 | 438篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
261.
A paradigm for studying oral sensory tactile function through use of single frequency vibration applied to the dorsal surface of the tongue was administered to a group of 10 young black women and 10 young white normal-speaking women. Analyses showed no differences between groups with regard to lingual vibrotactile threshold of sensitivity or suprathreshold magnitude-estimation scaling responses. 相似文献
262.
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
263.
This investigation was conducted to examine whether older adults would improve their performance when given statements intended to make them feel important to a research study as well as statements concerning their over-all well-being. Women (n = 14) and men (n = 15) with mean ages of 76.0 yr. and 75.1 yr., respectively, were randomly assigned into a control group, a positive reinforcement group, and a group given statements of personal importance. Dependent measures on a rotary pursuit task, screw-and-nut assembly task, and an interest questionnaire were obtained during three separate visits. Data were analyzed with a 3 x 3 (Groups x Days) analysis of variance. While no significant group effects were found on any measure, a significant main effect was obtained for days, indicative of learning. 相似文献
264.
The purpose of this study was to investigate differences in function of the tactile sensory system between groups of normal-speaking children and children with articulation problems. This task was accomplished by studying possible tactile threshold shifts occurring during magnitude-estimation scaling of vibratory stimuli presented to the dorsal surface of the tongue. 10 normal-speaking children (M age = 7.8 yr.) and 9 children with articulation problems (M age = 7.5 yr.) participated. The normal-speaking children and articulatory defective children performed differently on the magnitude-estimation scaling task in which threshold was allowed to return to baseline after each stimulus presentation. These two groups of children also showed dissimilar threshold shifts for the suprathreshold intensities employed in the magnitude-estimation scaling. 相似文献
265.
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
266.
Michael Thau 《Studia Logica》1992,51(2):241-248
We prove that all proofs in -logic (a first order logic with -rule added) in which -rule is used finitely many times can be turned into proofs in which the -rule is used at most one time. Next, we prove that the word finitely above cannot be changed by the word infinitely. 相似文献
267.
268.
L J?ncke 《Zeitschrift für experimentelle und angewandte Psychologie》1992,39(3):434-454
Twenty male subjects (Ss) were repeatedly confronted for five seconds to pictures with positive, negative and neutral valence. During the picture presentation facial EMG-reactions of five mimic muscles (m. frontalis lateralis, m. corrugator supercilii, m. orbicularis oculi, m. zygomaticus major on the right and left side of the face) were recorded. In addition, heart rate was measured. It could be shown that during repeated presentation of pictures with positive valence the m. orbicularis oculi and the m. zygomaticus major on both sides of the face yielded enhanced average EMG-reactions as compared to the repeated presentation of pictures with negative and neutral valence. During presentation of pictures with negative valence the m. frontalis lateralis and the m. corrugator supercilii revealed enhanced EMG-reactions as compared to the repeated presentation of pictures with positive valence. Furthermore, it could be shown that during the repeated presentation of pictures with positive valence those facial muscles which mainly react during confrontation with pictures of positive valence showed a continuous decrease of EMG-activity. Facial muscles which mainly react during the presentation of pictures with negative valence do not show a continuous decrease in EMG-activity during the course of the repeated presentation of pictures with negative valence. Additionally, the EMG-activity of the m. zygomaticus major on the right and lift side of the face do not differ with respect to the mean activity and the time course during confrontation of pictures with positive valence. The m. orbicularis oculi yielded enhanced EMG-reactions during the presentation of pictures with positive valence as compared to both m. zygomaticus major muscles. The present results are discussed with respect to psychobiological theories concerning facial expression. 相似文献
269.
Michael Bacharach 《Synthese》1992,91(3):247-284
According to decision theory, the rational initial action in a sequential decision-problem may be found by ‘backward induction’ or “folding back’. But the reasoning which underwrites this claim appeals to the agent's beliefs about what she will later believe, about what she will later believe she will still later believe, and so forth. There are limits to the ‘depth’ of people's beliefs. Do these limits pose a threat to the standard theory of rational sequential choice? It is argued, first, that the traditional solutions of certain games depend on knowledge which exceeds depth limits, and that these solutions therefore cannot be shown rational in the usual sense. Then, for that related reason even ‘folding back’ solutions of one-person problems cannot be! A revision of our notion of rational choice is proposed, analogous to the reliabilist account of knowledge of Goldman and others, by which this paradox is resolved. 相似文献
270.
The present research examined the role of phonological and orthographic properties of cues in mediating the retrieval of words from the mental lexicon. The task required subjects to resolve fragmented words when provided with semantically related cues (e.g., spiteful:---DIC----). Phonological properties of the letter cues were manipulated such that the letters either corresponded to the syllables (e.g., DIC in vindictive) or nonsyllables (NDI) in the word. Orthographic properties of the letter cues were manipulated by selecting letter groups that either co-occurred frequently in the language or did not. In two experiments, results revealed little or no effect of the phonological variable (syllables) but a reliable effect of the orthographic variable (letter-cue frequency). Letter cues with a low frequency of co-occurrence in the language led to better completion of the fragmented words. We interpret these findings as support for models of lexical representation that are based on orthographic properties (e.g., Seidenberg & McClelland, 1989) rather than those based on phonological constraints. 相似文献