首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1524篇
  免费   166篇
  国内免费   194篇
  1884篇
  2024年   9篇
  2023年   33篇
  2022年   41篇
  2021年   56篇
  2020年   72篇
  2019年   86篇
  2018年   107篇
  2017年   88篇
  2016年   75篇
  2015年   59篇
  2014年   47篇
  2013年   171篇
  2012年   96篇
  2011年   118篇
  2010年   79篇
  2009年   82篇
  2008年   95篇
  2007年   105篇
  2006年   96篇
  2005年   82篇
  2004年   45篇
  2003年   37篇
  2002年   22篇
  2001年   22篇
  2000年   17篇
  1999年   21篇
  1998年   9篇
  1997年   7篇
  1996年   7篇
  1995年   7篇
  1994年   8篇
  1993年   9篇
  1992年   13篇
  1991年   5篇
  1990年   1篇
  1989年   8篇
  1988年   3篇
  1987年   6篇
  1986年   3篇
  1985年   5篇
  1984年   5篇
  1983年   1篇
  1982年   6篇
  1981年   6篇
  1980年   4篇
  1979年   4篇
  1975年   3篇
  1972年   1篇
  1964年   1篇
  1959年   1篇
排序方式: 共有1884条查询结果,搜索用时 8 毫秒
161.
We investigated the relations between anticipation of sadness for excluded peers, sympathy, and prosocial behavior in a sample of 127 Italian preschoolers (Mage?=?4.84?years, SD?=?0.85). Children attributed emotions to hypothetical excluded peers who exhibited withdrawn versus aggressive behavior, and these attributions were coded for the presence and intensity of sadness. Teachers rated children’s sympathy and prosocial behavior via questionnaire. In general, children attributed more sadness to the withdrawn excluded peer than the aggressive excluded peer. A path analysis revealed that those who anticipated higher levels of sadness for the withdrawn excluded peer were rated higher in sympathy and, in turn, higher in prosocial behavior. Attributing high levels of sadness to withdrawn excluded peers—who portray relatively heightened need—may be an early social-emotional characteristic of children who are more sympathetic and more likely to channel other-oriented concerns into prosocial actions.  相似文献   
162.
The purpose of this study was to investigate the differences of knee concentric and eccentric strength and impact related knee biomechanics between jumpers and non-jumpers during step-off landing tasks. Ten male college swimming athletes (non-jumpers) and 10 track and volleyball athletes (jumpers) were recruited to participate in two test sessions: a muscle strength testing session of concentric and eccentric extension for dominant knee joint at 60 °/s and 180 °/s and a landing testing session. The participants performed five trials of step-off landing in each of four conditions: soft and stiff landing from 0.4 m and 0.6 m landing heights. The three-dimensional kinematics and ground reaction force were recorded simultaneously during step-off landing conditions. The results showed that the jumpers had significantly greater peak knee eccentric extension and concentric flexion torques compared to the non-jumpers. No significant group effects were found for peak vertical ground reaction force and knee range of motion during landing. The jumpers had significantly greater knee contact flexion angle, maximum knee flexion angle and initial knee extension moment compared to the non-jumpers. These results suggest that these athletes adopted a favorable impact attenuation strategy that is related to the greater knee eccentric muscle strength and training.  相似文献   
163.
Past research generally suggests that East Asians tolerate opposing feelings or dialectical emotions more than North Americans. We tested the idea that North Americans would have fewer opposing emotions than East Asians in positive, but not in negative or mixed situations. Forty-seven European American, 40 Chinese, and 121 Japanese students reported the emotions that a protagonist of standardised positive, negative, and mixed situations would feel. Emotions were coded into three valence categories: pleasant, unpleasant, and neither-pleasant-nor-unpleasant. As predicted, cultural differences in opposing emotion associations were found in positive situations only. Moreover, East Asians reported more neither-pleasant-nor-unpleasant feelings, especially in mixed situations, possibly reflecting a deferral of valence appraisal due to expected change.  相似文献   
164.
Although the state space approach for estimating multilevel regression models has been well established for decades in the time series literature, it does not receive much attention from educational and psychological researchers. In this article, we (a) introduce the state space approach for estimating multilevel regression models and (b) extend the state space approach for estimating multilevel factor models. A brief outline of the state space formulation is provided and then state space forms for univariate and multivariate multilevel regression models, and a multilevel confirmatory factor model, are illustrated. The utility of the state space approach is demonstrated with either a simulated or real example for each multilevel model. It is concluded that the results from the state space approach are essentially identical to those from specialized multilevel regression modeling and structural equation modeling software. More importantly, the state space approach offers researchers a computationally more efficient alternative to fit multilevel regression models with a large number of Level 1 units within each Level 2 unit or a large number of observations on each subject in a longitudinal study.  相似文献   
165.
This study investigated how different doses of alcohol affected eyewitness recall. Participants (N = 126) were randomly assigned to three groups with different blood alcohol concentration (BAC), either a control group (mean BAC 0.00%, = 42), a lower alcohol dose group (mean BAC 0.04%, = 40), or a higher alcohol dose group (mean BAC 0.06%, = 44). After consumption, participants witnessed a movie of a mock crime and were interviewed one week later. The main results showed that witnesses with the higher intoxication level recalled fewer details compared to witnesses with the lower intoxication level. The amount of alcohol consumed did not have an impact on the accuracy rate. No sex differences were found. The results are discussed in the light of past research. We conclude that more studies are needed before recommendations can be made to an applied setting.  相似文献   
166.
Threat relates to right‐wing ideological attitudes at the individual level. The present study aims to extend this relationship to the national level. More specifically, in a sample of 91 nations, we collected country‐level indicators of threat (including inflation, unemployment, gross national product, homicide rate, and life expectancy). Moreover, we analyzed data from the European and World Value Survey (total N = 134,516) to obtain aggregated country‐level indicators for social‐cultural and economic‐hierarchical right‐wing attitudes for each of these countries. In accordance with previous findings based on the individual level, a positive relationship between threat indicators and right‐wing attitudes emerged. This relationship was stronger than what was usually reported at the individual level. In the discussion, we focus on the mutually reinforcing influence at the individual and national levels in terms of right‐wing attitudes.  相似文献   
167.
This review investigates the presence of young children’s model-based cultural transmission biases in social learning, arguing that such biases are adaptive and flexible. Section 1 offers five propositions regarding the presence and direction of model-based transmission biases in young children’s copying of a model. Section 2 discusses the cognitive abilities required for differing model-based biases and tracks their development in early childhood. Section 3 suggests future areas of research including considering the social aspect of model-based biases and understanding their use within a comparative perspective.  相似文献   
168.
The association between specific language impairment (SLI), attention deficit/hyperactivity disorder (ADHD), and working memory (WM) was examined. WM has been implicated in language acquisition and models of ADHD; however, evidence for WM deficits in SLI and ADHD has been inconsistent. The components of Baddeley's WM model were investigated in 18 children with SLI, 16 children with ADHD, 11 children with comorbid SLI+ADHD, and 24 typically developing (TD) children. The presence of SLI resulted in deficits in more components of WM than the presence of ADHD indicating that children with SLI are more vulnerable to WM deficits than those with ADHD.  相似文献   
169.
A phase transition of MgS under high pressure is investigated using a first-principles method. It is found from energy-volume calculations that the rock-salt (B1) phase of MgS transforms into a FeSi-type (B28) phase at 143?GPa. The calculated ground-state parameters in the B1 phase are in excellent agreement with available experimental and theoretical data. Ab initio phonon calculations are also performed to investigate the structural behaviour of MgS under high pressure. An unstable transverse acoustic mode and a phase transition from B1 to B28 phase at ~143.7?GPa driven by this soft mode are predicted. The B28 structure of MgS is stable up to 350?GPa according to lattice dynamics calculations.  相似文献   
170.

High-resolution grazing-incidence parallel-beam powder diffraction has been used to detect the subsurface damage below alumina surfaces subjected to polishing with cerium oxide or diamond. Despite very significant evolution of the surface morphology, no changes in the subsurface strains were observed over a 20min period of polishing with ceria. For both polishing materials, the variation with angle in the full-width at half-height maximum was successfully modelled by a strain distribution that fell exponentially with increasing depth. Although the surface amplitude and depth dependence parameter are coupled, we have been able to place upper limits on the depth to which the damage extends. Under realistic assumptions, the depth of damage induced by 1µm diamond paste is comparable with that from 3µm ceria polish.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号