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   2146篇
  免费   248篇
  国内免费   396篇
  2024年   3篇
  2023年   36篇
  2022年   45篇
  2021年   88篇
  2020年   105篇
  2019年   75篇
  2018年   95篇
  2017年   99篇
  2016年   95篇
  2015年   67篇
  2014年   75篇
  2013年   173篇
  2012年   116篇
  2011年   176篇
  2010年   138篇
  2009年   160篇
  2008年   178篇
  2007年   206篇
  2006年   204篇
  2005年   167篇
  2004年   89篇
  2003年   70篇
  2002年   45篇
  2001年   24篇
  2000年   33篇
  1999年   30篇
  1998年   25篇
  1997年   20篇
  1996年   25篇
  1995年   13篇
  1994年   10篇
  1993年   14篇
  1992年   13篇
  1991年   4篇
  1990年   7篇
  1989年   5篇
  1988年   3篇
  1987年   3篇
  1985年   6篇
  1984年   6篇
  1983年   7篇
  1982年   10篇
  1981年   6篇
  1980年   5篇
  1979年   3篇
  1971年   2篇
  1968年   2篇
  1966年   3篇
  1964年   1篇
  1953年   1篇
排序方式: 共有2790条查询结果,搜索用时 31 毫秒
191.
Cellular precipitation (also known as discontinuous precipitation) has been observed at the grain boundaries of a newly developed nickel-based Inconel740H alloy designed for use at 700?°C in advanced ultrasupercritical coal-fired power plants. By means of element mapping and selected area diffraction, the cellular precipitates were identified as Cr-rich M23C6 carbides. The onset of cellular precipitation was found to follow a pucker mechanism in Inconel740H. The cellular precipitates at the grain boundaries, even at low volume fractions, were severely detrimental to the creep strength at 750?°C. The creep rupture life of Inconel740H containing cellular precipitates at grain boundaries was only one-tenth of that for the alloy without cellular precipitates. The reason for the drastically decreased creep rupture life is attributed to the poor resistance of cellular precipitates to crack propagation during creep.  相似文献   
192.
有关辩证情绪的实证研究已经成为情绪研究中的一个新的热点问题,并从一个本土心理学的研究领域演变为主流心理学的研究课题。辩证情绪是指积极和消极情绪的共存。文章对辩证情绪的研究方法进行了回顾,主要包括辩证情绪研究范式的演变、辩证情绪的诱发方法、辩证情绪的测量方法以及辩证情绪的计算方法,并对不同的研究方法的优缺点及其贡献进行了比较和分析。最后,文章对辩证情绪研究方法的未来发展提出了展望。  相似文献   
193.
该研究以广州市与台中市大学生为被试,抽取500人为预测样本及800人为正式施测样本,通过探索性因素分析和验证性因素分析编制生命意义量表,并通过t检验和潜在剖面分析考察两岸大学生生命意义现况的差异.结果表明:(1)编制的生命意义量表由存在意义、追寻意义、存在盈实、苦难接纳、死亡接纳以及求意义的意志等6个维度组成,具有良好的信度和效度.(2)两岸大学生生命意义总体无显著差异;存在盈实、苦难接受与死亡接纳维度有显著或非常显著的差异.(3)潜在剖面分析结果显示,两岸大学生生命意义类型相似.Wald检验结果表明,对于“死亡接纳”维度,台湾与大陆学生在各潜在类别的均分上存在显著的差异.  相似文献   
194.
195.
Humans rely on two main systems of quantification; one is nonsymbolic and involves approximate number representations (known as the approximate number system or ANS), and the other is symbolic and allows for exact calculations of number. Despite the pervasiveness of the ANS across development, recent studies with adolescents and school-aged children point to individual differences in the precision of these representations that, importantly, have been shown to relate to symbolic math competence even after controlling for general aspects of intelligence. Such findings suggest that the ANS, which humans share with nonhuman animals, interfaces specifically with a uniquely human system of formal mathematics. Other findings, however, point to a less straightforward picture, leaving open questions about the nature and ontogenetic origins of the relation between these two systems. Testing children across the preschool period, we found that ANS precision correlated with early math achievement but, critically, that this relation was nonlinear. More specifically, the correlation between ANS precision and math competence was stronger for children with lower math scores than for children with higher math scores. Taken together, our findings suggest that early-developing connections between the ANS and mathematics may be fundamentally discontinuous. Possible mechanisms underlying such nonlinearity are discussed.  相似文献   
196.
A 2-year longitudinal study was conducted to test 3 causal models about adolescent autonomy, filial piety, beliefs about parental authority, and obedience in terms of personal, prudential, and multifaceted issues. Four hundred and thirty-six students from 10 junior and senior high schools in Taiwan (boys, n = 223; senior high school, n = 211) participated in the study. Hypothesis 1 predicted that autonomy (individuating autonomy vs. relating autonomy) would positively correlate with beliefs about authority legitimacy and obligation to obey, but was not supported. Hypothesis 2 predicted that filial piety (authoritarian piety vs. reciprocal piety) would positively associate with authority beliefs, and was partially supported. Authoritarian piety showed the positive relation with authority beliefs. Hypothesis 3 predicted that beliefs about authority legitimacy and obligation to obey would positively associate with obedience, and was supported. Hypothesis 4 predicted that age might moderate the structure models across domains, but the results indicated that age did not moderate the structural model in the prudential and multifaceted domains. The overall findings of this study reveal that adolescent beliefs about authority serve as a mediator between authoritarian piety and obedience, suggesting that traditional piety still has an influence on parent–child interaction in today's society.  相似文献   
197.
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   
198.
The current study aimed to analyze the importance of trait emotional intelligence in life satisfaction and to extend the previous literature by investigating the potential mediating effects of resilience and affect balance in this relationship. To test the study hypotheses, self-report measures of trait emotional intelligence, resilience, positive and negative affect, and life satisfaction were administrated to 263 undergraduates. Correlation analysis indicated that trait emotional intelligence was positively correlated with life satisfaction. Mediational analyses showed that trait emotional intelligence exerted its indirect effect on life satisfaction through the simple mediating effect of affect balance and the three-path mediating effect of resilience–affect balance. In addition, resilience played as a partial mediator between trait emotional intelligence and affect balance. Furthermore, multi-group analyses showed that the mediational model was not moderated by gender. Therefore, this study makes a contribution to the complex nature of the association between trait emotional intelligence and subjective well-being.  相似文献   
199.
Gambling near‐misses are non‐rewarded events that resemble a winning configuration. Past research using slot machines has shown that moderate rates of near‐misses increase gambling persistence, but the mechanisms supporting this persistence are unclear. One hypothesis is that near‐misses are mistakenly interpreted as signals of skill acquisition, supporting learning and fuelling the ‘illusion of control’. A slot machine simulation was administered to 60 volunteers, with ratings of the perceived chances of winning, pleasure and motivation to play following particular outcomes. Psychophysiological measures (electrodermal activity and heart rate) were taken, and gambling persistence was measured after 30 trials. Near‐misses were similar to full‐miss outcomes in that they were regarded as unpleasant. However, near‐misses were akin to win outcomes in that they increased motivations to play and electrodermal activity. Learning was evidenced by the expectancy of winning increasing following wins and decreasing after losses. Although there was no overall change in expectancy of winning after near‐misses across all participants, those subjects reporting a greater increase in the expectancy of winning following a near‐miss showed more persistent play, consistent with the learning hypothesis. Greater heart rate acceleration following near‐misses was also associated with persistence. We also observed differential effects of near‐misses where the reel stopped either side of the winning position (‘payline’): motivational effects were restricted to near‐misses stopping before the payline, whereas near‐misses that stopped after the payline were primarily aversive. The payline effects are not predicted by the learning hypothesis and may indicate an affective component to near‐misses, possibly linked to counterfactual processing. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
200.
The present study aims to explore the influence of emotional context on word evaluation. Participants were asked to read an “adjective + noun” phrase, where the adjective could be a positive or negative word, and the noun could be a positive, neutral or negative word, and then to make an emotional evaluation on the emotional tone of the target noun based on a 9-point Likert scale. In a control condition, an isolated noun was presented with no context. Results showed that positive context made the evaluation of target words bias toward positive tone, while negative context shaped the evaluation of target words toward negative tone. The modulatory effect of negative context was greater than that of positive context in shaping evaluation of emotional words with opposite valence. Moreover, the modulatory effect of emotional context was constrained by the inherent meaning of target word. The present study demonstrated the flexibility as well as the relative stability of emotional meaning of word.  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