全文获取类型
收费全文 | 8463篇 |
免费 | 269篇 |
国内免费 | 3篇 |
专业分类
8735篇 |
出版年
2019年 | 98篇 |
2018年 | 181篇 |
2017年 | 154篇 |
2016年 | 141篇 |
2015年 | 117篇 |
2014年 | 134篇 |
2013年 | 706篇 |
2012年 | 274篇 |
2011年 | 260篇 |
2010年 | 138篇 |
2009年 | 155篇 |
2008年 | 228篇 |
2007年 | 238篇 |
2006年 | 237篇 |
2005年 | 192篇 |
2004年 | 196篇 |
2003年 | 178篇 |
2002年 | 197篇 |
2001年 | 253篇 |
2000年 | 244篇 |
1999年 | 191篇 |
1998年 | 96篇 |
1997年 | 94篇 |
1996年 | 113篇 |
1994年 | 85篇 |
1993年 | 94篇 |
1992年 | 147篇 |
1991年 | 150篇 |
1990年 | 149篇 |
1989年 | 126篇 |
1988年 | 114篇 |
1987年 | 135篇 |
1986年 | 135篇 |
1985年 | 134篇 |
1984年 | 130篇 |
1983年 | 113篇 |
1982年 | 86篇 |
1981年 | 89篇 |
1979年 | 129篇 |
1978年 | 96篇 |
1977年 | 92篇 |
1976年 | 87篇 |
1975年 | 95篇 |
1974年 | 110篇 |
1973年 | 115篇 |
1970年 | 91篇 |
1969年 | 89篇 |
1968年 | 115篇 |
1967年 | 89篇 |
1966年 | 96篇 |
排序方式: 共有8735条查询结果,搜索用时 0 毫秒
911.
912.
913.
Four studies were conducted to develop and validate the Coping With Discrimination Scale (CDS). In Study 1, an exploratory factor analysis (N = 328) identified 5 factors: Education/Advocacy, Internalization, Drug and Alcohol Use, Resistance, and Detachment, with internal consistency reliability estimates ranging from .72 to .90. In Study 2, a confirmatory factor analysis (N = 328) provided cross-validation of the 5-factor model as well as evidence for validity of the scale. The validity evidence was similar across racial groups and for males and females. In Study 3, the estimated 2-week test-retest reliabilities (N = 53) were between .48 and .85 for the 5 factors. Education/Advocacy, Internalization, Drug and Alcohol Use, and Detachment were positively associated with active coping, self-blame, substance use, and behavioral disengagement, respectively, providing further support for validity of the CDS. Finally, incremental validity evidence was obtained in Study 4 (N = 220), where it was shown that the CDS explained variance in outcome variables (i.e., depression, life satisfaction, self-esteem, and ethnic identity) that could not be explained by general coping strategies. 相似文献
914.
915.
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
916.
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
917.
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
918.
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
919.
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
920.
In creativity, there is scant evidence of significant racial and gender differences, and when such differences are found, there is no consistency regarding which groups perform best. There has been little work focusing on racial and gender biases and/or stereotypes within creativity assessment. It is study these issues by using a modified version of the Consensual Assessment Technique in which the judges are provided with information about the creators' gender and/or race. A total of 455 undergraduates assigned ratings for creativity, writing ability, and enjoyment to 60 poems downloaded from a poetry Web site. These poems either had no attribution or had (fictional) stereotypical Black, White, and Crossover names for each gender. Results suggest that novice raters using CAT methodology display little evidence of bias in their ratings of creativity, writing ability, and poem enjoyment. Very slight preference was found for poems assigned names of White females. 相似文献