全文获取类型
收费全文 | 514篇 |
免费 | 44篇 |
国内免费 | 74篇 |
专业分类
632篇 |
出版年
2024年 | 2篇 |
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 13篇 |
2020年 | 36篇 |
2019年 | 20篇 |
2018年 | 21篇 |
2017年 | 29篇 |
2016年 | 24篇 |
2015年 | 16篇 |
2014年 | 15篇 |
2013年 | 50篇 |
2012年 | 22篇 |
2011年 | 32篇 |
2010年 | 25篇 |
2009年 | 28篇 |
2008年 | 34篇 |
2007年 | 41篇 |
2006年 | 30篇 |
2005年 | 28篇 |
2004年 | 22篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 16篇 |
1998年 | 13篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 9篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有632条查询结果,搜索用时 11 毫秒
591.
Overexpression of and RNA interference with the CCAAT enhancer-binding protein on long-term facilitation of Aplysia sensory to motor synapses 总被引:3,自引:0,他引:3 下载免费PDF全文
Lee JA Kim HK Kim KH Han JH Lee YS Lim CS Chang DJ Kubo T Kaang BK 《Learning & memory (Cold Spring Harbor, N.Y.)》2001,8(4):220-226
In the marine mollusk Aplysia, the CCAAT/enhancer-binding protein, ApC/EBP, serves as an immediate early gene in the consolidation of long-term facilitation in the synaptic connection between the sensory and motor neurons of the gill-withdrawal reflex. To further examine the role of ApC/EBP as a molecular switch of a stable form of long-term memory, we cloned the full-length coding regions of two alternatively spliced forms, the short and long form of ApC/EBP. Overexpression of each isoform by DNA microinjection resulted in a l6-fold increase in the expression of the coinjected luciferase reporter gene driven by an ERE promoter. In addition, when we overexpressed ApC/EBP in Aplysia sensory neurons, we found that the application of a single pulse of 5-HT that normally induced only short-term facilitation now induced long-term facilitation. Conversely, when we attempted to block the synthesis of native ApC/EBP by microinjecting double-strand RNA or antisense RNA, we blocked long-term facilitation in a sequence-specific manner. These data support the idea that ApC/EBP is both necessary and sufficient to consolidate short-term memory into long-term memory. Furthermore, our results suggest that this double-strand RNA interference provides a powerful tool in the study of the genes functioning in learning and memory in Aplysia by specifically inhibiting both the constitutive and induced expression of the genes. 相似文献
592.
The nature of shear flow lines in equal-channel angular-pressed (ECAPed) metals has been investigated experimentally and theoretically. Experimental results indicate that, for metals pressed in a right-angle die, the shear flow lines often have an angle of ~27° with respect to the extrusion direction. It is suggested that the shear flow lines are composed of a group of elongated grains with an elongation direction that deviates slightly from that of the shear flow lines. 相似文献
593.
Bing Q. Han Enrique J. Lavernia Farghalli A. Mohamed 《Philosophical Magazine Letters》2013,93(2):89-96
The mechanical behaviour of bulk ultrafine-grained Al-7.5 wt% Mg alloy consolidated from cryomilled powders has been investigated. The experimental data show that the alloy exhibits high strength, low strain hardening, serrated flow and relatively high ductility. In addition, the data indicate that the yield strength in tension is essentially equal to that in compression. The yield and flow strengths of the alloy are discussed in terms of strengthening processes that are related to grain size, the Orowan mechanism and solid-solution hardening. The serrations in the stress-strain curve are discussed in terms of dynamic strain ageing and deformation twinning. 相似文献
594.
The surface tension of undercooled liquid cobalt has been measured by the oscillating-drop technique combined with electromagnetic levitation. The accuracy of the method was verified by measurements of the surface tension of liquid nickel. The liquid cobalt was undercooled by up to 231K (0.13T m), and its surface tension determined to be σCo =1875 0.348(T-T m)mNm-1. From this result, the viscosity, self-diffusion coefficient, density and thermal diffusivity of undercooled liquid cobalt were derived. Using these thermophysical parameters, the growth velocity of cobalt dendrite is calculated and shown to agree well with experimental results. Furthermore, the Marangoni number and the Rayleigh number are calculated; these increase slowly with increasing degree of undercooling. 相似文献
595.
Dylan Molenaar Francis Tuerlinckx Han L. J. van der Maas 《Multivariate behavioral research》2013,48(1):56-74
A generalized linear modeling framework to the analysis of responses and response times is outlined. In this framework, referred to as bivariate generalized linear item response theory (B-GLIRT), separate generalized linear measurement models are specified for the responses and the response times that are subsequently linked by cross-relations. The cross-relations can take various forms. Here, we focus on cross-relations with a linear or interaction term for ability tests, and cross-relations with a curvilinear term for personality tests. In addition, we discuss how popular existing models from the psychometric literature are special cases in the B-GLIRT framework depending on restrictions in the cross-relation. This allows us to compare existing models conceptually and empirically. We discuss various extensions of the traditional models motivated by practical problems. We also illustrate the applicability of our approach using various real data examples, including data on personality and cognitive ability. 相似文献
596.
597.
Although studies on the association between social capital and subjective well-being have been recently increasing many issues still remain unsolved. The purpose of this study is to investigate the association between various social capital dimensions both at the individual (political participation, network source, trust, and organizational participation) and area level (voting rate, trust, and organizational participation) and subjective well-being (happiness) using multilevel analysis while controlling for various control variables at multiple levels. Survey data was collected from December, 2010 to April, 2011 in Seoul, South Korea. The final sample was comprised of 4,585 respondents within all 25 administrative areas in Seoul. Results from the multilevel analysis revealed that all individual and area level (trust) social capital variables are positively associated with subjective happiness. Our findings also point to the need for more sophisticated studies with longitudinal datasets based on multilevel framework using instrumental variable analysis to clarify our knowledge regarding the effects of social capital on subjective well-being. 相似文献
598.
599.
Jonas Dalege Denny Borsboom Frenk van Harreveld Han L. J. van der Maas 《Psychological inquiry》2013,24(4):175-193
AbstractThis article introduces the Attitudinal Entropy (AE) framework, which builds on the Causal Attitude Network model that conceptualizes attitudes as Ising networks. The AE framework rests on three propositions. First, attitude inconsistency and instability are two related indications of attitudinal entropy, a measure of randomness derived from thermodynamics. Second, energy of attitude configurations serves as a local processing strategy to reduce the global entropy of attitude networks. Third, directing attention to and thinking about attitude objects reduces attitudinal entropy. We first discuss several determinants of attitudinal entropy reduction and show that several findings in the attitude literature, such as the mere thought effect on attitude polarization and the effects of heuristic versus systematic processing of arguments, follow from the AE framework. Second, we discuss the AE framework’s implications for ambivalence and cognitive dissonance. 相似文献
600.
A generalized linear factor model approach to the hierarchical framework for responses and response times 下载免费PDF全文
Dylan Molenaar Francis Tuerlinckx Han L. J. van der Maas 《The British journal of mathematical and statistical psychology》2015,68(2):197-219
We show how the hierarchical model for responses and response times as developed by van der Linden (2007), Fox, Klein Entink, and van der Linden (2007), Klein Entink, Fox, and van der Linden (2009), and Glas and van der Linden (2010) can be simplified to a generalized linear factor model with only the mild restriction that there is no hierarchical model at the item side. This result is valuable as it enables all well‐developed modelling tools and extensions that come with these methods. We show that the restriction we impose on the hierarchical model does not influence parameter recovery under realistic circumstances. In addition, we present two illustrative real data analyses to demonstrate the practical benefits of our approach. 相似文献