全文获取类型
收费全文 | 9589篇 |
免费 | 382篇 |
国内免费 | 5篇 |
专业分类
9976篇 |
出版年
2021年 | 91篇 |
2020年 | 112篇 |
2019年 | 164篇 |
2018年 | 271篇 |
2017年 | 263篇 |
2016年 | 248篇 |
2015年 | 178篇 |
2014年 | 203篇 |
2013年 | 873篇 |
2012年 | 420篇 |
2011年 | 412篇 |
2010年 | 208篇 |
2009年 | 248篇 |
2008年 | 365篇 |
2007年 | 373篇 |
2006年 | 296篇 |
2005年 | 273篇 |
2004年 | 272篇 |
2003年 | 253篇 |
2002年 | 244篇 |
2001年 | 256篇 |
2000年 | 246篇 |
1999年 | 182篇 |
1998年 | 103篇 |
1997年 | 90篇 |
1996年 | 93篇 |
1995年 | 76篇 |
1993年 | 80篇 |
1992年 | 128篇 |
1991年 | 128篇 |
1990年 | 124篇 |
1989年 | 108篇 |
1988年 | 93篇 |
1987年 | 104篇 |
1986年 | 112篇 |
1985年 | 113篇 |
1984年 | 102篇 |
1983年 | 89篇 |
1979年 | 100篇 |
1978年 | 73篇 |
1975年 | 68篇 |
1974年 | 94篇 |
1973年 | 100篇 |
1972年 | 72篇 |
1971年 | 70篇 |
1970年 | 80篇 |
1969年 | 75篇 |
1968年 | 106篇 |
1967年 | 82篇 |
1966年 | 93篇 |
排序方式: 共有9976条查询结果,搜索用时 15 毫秒
981.
Kathleen Moritz Rudasill Thomas G. Reio Jr. Jennifer E. Taylor 《Journal of School Psychology》2010,48(5):389-412
This study examines the mediating role of student-teacher relationship quality (conflict and closeness) in grades 4, 5, and 6 on the relation between background characteristics, difficult temperament at age 4½ and risky behavior in 6th grade. The longitudinal sample of participants (N = 1156) was from the NICHD Study of Early Child Care and Youth Development. Structural equation modeling was used to estimate paths from (a) background characteristics to student-teacher relationship quality and risky behavior, (b) temperament to student-teacher relationship quality and risky behavior, and (c) student-teacher relationship quality to risky behavior. Findings indicate that students' family income, gender, receipt of special services, and more difficult temperament were associated with risky behavior. In addition, student-teacher conflict was a mediator. Students with more difficult temperaments were more likely to report risky behavior and to have conflict in their relationships with teachers. More conflict predicted more risky behavior. Closer student-teacher relationships were associated with less risky behavior. Results suggest negative relationships, specifically student-teacher relationships, may increase the risk that certain adolescents will engage in risky behavior. 相似文献
982.
Michel B. C. Sokolowski Gérald Disma Charles I. Abramson 《Journal of the experimental analysis of behavior》2010,93(1):81-89
An operant conditioning situation for the blow fly (Protophormia terrae novae) is described. Individual flies are trained to enter and reenter a hole as the operant response. Only a few sessions of contingent reinforcement are required to increase response rates. When the response is no longer followed by food, the rate of entering the hole decreases. Control procedures revealed that rate of responding is not a simple overall result of feeding or of aging. The flies entered into the hole only if the response was required to obtain the food. 相似文献
983.
David I. Waddington 《Studies in Philosophy and Education》2010,29(4):351-364
One of the interesting aspects of Dewey’s early educational thought is his apparent hostility toward children’s imaginative
pursuits, yet the question of why this antipathy exists remains unanswered. As will become clear, Dewey’s hostility towards
imaginative activities stemmed from a broad variety of concerns. In some of his earliest work, Dewey adopted a set of anti-Romantic
criticisms and used these concerns to attack what one might call “runaway” imaginative and emotional tendencies. Then, in
his early educational writings, these earlier concerns were augmented by several other factors, including problematic trends
in progressive education, new developments in psychology, and Dewey’s own educational aims. This analysis explores the roots
of these criticisms, and explains how they culminate in the stance on the imagination that Dewey eventually outlined in the
early educational writings. Notably, these findings have some important implications for certain prominent contemporary critics
of progressivism. 相似文献
984.
David Schultz Archana Ambike Sean Kevin Logie Katherine E. Bohner Laura M. Stapleton Holly VanderWalde Christopher B. Min Jennifer A. Betkowski 《Journal of abnormal child psychology》2010,38(5):601-613
Crick and Dodge’s (Psychological Bulletin 115:74–101, 1994) social information processing model has proven very useful in guiding research focused on aggressive and peer-rejected children’s
social-cognitive functioning. Its application to early childhood, however, has been much more limited. The present study responds
to this gap by developing and validating a video-based assessment tool appropriate for early childhood, the Schultz Test of
Emotion Processing—Preliminary Version (STEP-P). One hundred twenty-five Head Start preschool children participated in the
study. More socially competent children more frequently attributed sadness to the victims of provocation and labeled aggressive
behaviors as both morally unacceptable and less likely to lead to positive outcomes. More socially competent girls labeled
others’ emotions more accurately. More disruptive children more frequently produced physically aggressive solutions to social
provocations, and more disruptive boys less frequently interpreted social provocations as accidental. The STEP-P holds promise
as an assessment tool that assesses knowledge structures related to the SIP model in early childhood. 相似文献
985.
This paper is concerned with the implications of vacancy-pair mechanisms on chemical diffusion in intermetallic compounds with the B2 structure. The discussion specifically includes the so-called triple-defect mechanism. It is shown that the vacancy-pair mechanism cannot contribute to chemical diffusion in the intermetallic compound at the stoichiometric composition AB. Focusing on the triple-defect mechanism we extend it to non-stoichiometric compositions by including isolated antistructural atoms. By means of Monte Carlo simulation we show that the efficiency of the triple-defect mechanism in providing for chemical diffusion increases linearly with increasing antistructural atom composition but the efficiency remains relatively low unless the composition is highly non-stoichiometric. 相似文献
986.
An enhancement of the UV-visible optical absorption spectra of Ag nanoparticles (NPs) deposited on indium tin oxide (ITO) surfaces of different resistance by a seed-mediated growth technique is presented. A bicolour coherent beam, obtained from a pulsed Nd:YAG laser providing a 1060-nm fundamental wavelength and a double-frequency one at 530?nm, was used. A significant change in the optical density is observed for Ag NPs on low-resistance ITO surfaces (≈4?Ω/square), while almost nothing occurs with high-resistance (≈50?Ω/square surfaces). The spectral position of the maximal absorption at 440?nm is almost preserved in both cases. This result is explained in terms of a local photoinduced static field and surface-plasmon polaritons interacting with photoexcited phonons. A grating effect, arising from the coherent bicolour light forming a superstructure as for quantum crystals, could be another contribution. 相似文献
987.
It is known that the binary Cu–2?wt.% Be alloy can be strengthened by ageing its supersaturated solution at 523?K. The increase in the strength arising from ageing is because of the formation of GP zones. The same level of strength is achieved by ageing the supersaturated solid solution of a dilute binary Cu–4?wt.% Ti alloy at 723?K. In contrast to Cu–2?wt.% Be alloy, the increase in strength in this alloy occurs on account of spinodal decomposition of the as-quenched microstructure through the mechanism of clustering and ordering. In the present study, decomposition of a supersaturated solid solution of the ternary Cu–4?wt.% Ti–2?wt.% Be alloy was studied. Whereas ageing of this alloy at 523?K resulted in the formation of GP zones like in a Cu–2?wt.% Be alloy, ageing at 723?K resulted in a spinodally decomposed microstructure as in a Cu–4?wt.% Ti alloy. The decomposition of the ternary alloy at the two temperatures by two different mechanisms indicates that Be and Ti in solution in Cu act, more or less, independently of each other during ageing. 相似文献
988.
Jennifer E. Porter 《Science as culture》2013,22(1):1-21
This article examines a narrative dilemma that popular texts on evolution face. On the one hand, popular science tends to privilege linear and culturally familiar narrative structures, as previous studies of popularization have often emphasized. On the other hand, however, the Darwinian idea of natural selection resists linear narration, as narrative theorist H. Porter Abbott has argued. This resistance arises from the fact that evolution by natural selection lacks proper narrative entities and narrative events and that it relies on two parallel narrative levels, the levels of species and organism. This paper explores how two popular science books on evolution negotiate this narrative dilemma by introducing a third narrative level. Both texts appropriate characteristics from the narrative levels of species and organism and project them on molecular and minute scales by portraying evolution as a micro-narrative that takes place in chromosomes, genes, cells and microscopic details of human organs. While this textual strategy produces a coherent and compelling narrative that for the most part succeeds in masking the structural gap between the narrative levels of species and organism, it also risks naturalizing cultural imagery. In particular, this micro-narrative tends to represent popular gender ideologies as biological truths embedded in molecular processes within our bodies. 相似文献
989.
ABSTRACTFlashbulb memories are vivid, confidently held, long-lasting memories for the personal circumstances of learning about an important event. Importance is determined, in part, by social group membership. Events that are relevant to one’s social group, and furthermore, are congruent with the prior beliefs of that group, should be more likely to be retained as flashbulb memories. The Fukushima nuclear disaster was relevant to ongoing political conversations in both Germany and the Netherlands, but, while the disaster was congruent with German beliefs about the dangers of nuclear energy, it was incongruent with Dutch support for nuclear power. Danish participants would not have found the disaster to be particularly relevant. Partially consistent with this prediction, across two samples (N?=?265 and N?=?518), German participants were most likely to have flashbulb memories for the Fukushima disaster. Furthermore, event features thought to be related to flashbulb memory formation (e.g. ratings of importance and consequentiality) also differed as a function of nationality. Spontaneously generated flashbulb memories for events other than Fukushima also suggested that participants reported events that were relevant to national identity (e.g. the Munich attacks for Germans, the Utøya massacre for Danes, and Malaysian Airlines flight MH-17 for Dutch participants). 相似文献
990.
The production effect is the finding that words spoken aloud at study are subsequently remembered better than are words read silently at study. According to the distinctiveness account, aloud words are remembered better because the act of speaking those words aloud is encoded and later recovery of this information can be used to infer that those words were studied. An alternative account (the strength-based account) is that memory strength is simply greater for words read aloud. To discriminate these two accounts, we investigated study mode judgements (i.e., “aloud”/”silent”/”new” ratings): The strength-based account predicts that “aloud” responses should positively correlate with memory strength, whereas the distinctiveness account predicts that accuracy of study mode judgements will be independent of memory strength. Across three experiments, where the strength of some silent words was increased by repetition, study mode was discriminable regardless of strength—even when the strength of aloud and repeated silent items was equivalent. Consistent with the distinctiveness account, we conclude that memory for “aloudness” is independent of memory strength and a likely candidate to explain the production effect. 相似文献