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   1563篇
  免费   159篇
  国内免费   449篇
  2024年   4篇
  2023年   25篇
  2022年   51篇
  2021年   62篇
  2020年   82篇
  2019年   55篇
  2018年   68篇
  2017年   62篇
  2016年   54篇
  2015年   56篇
  2014年   68篇
  2013年   132篇
  2012年   94篇
  2011年   135篇
  2010年   112篇
  2009年   105篇
  2008年   113篇
  2007年   181篇
  2006年   148篇
  2005年   122篇
  2004年   65篇
  2003年   49篇
  2002年   30篇
  2001年   24篇
  2000年   28篇
  1999年   36篇
  1998年   18篇
  1997年   15篇
  1996年   9篇
  1995年   14篇
  1994年   16篇
  1993年   13篇
  1992年   12篇
  1991年   13篇
  1990年   9篇
  1989年   13篇
  1988年   11篇
  1987年   6篇
  1986年   4篇
  1985年   9篇
  1984年   10篇
  1983年   7篇
  1982年   8篇
  1981年   9篇
  1980年   3篇
  1979年   6篇
  1963年   1篇
  1960年   1篇
  1957年   2篇
  1954年   1篇
排序方式: 共有2171条查询结果,搜索用时 15 毫秒
91.
It is known that electromyostimulation (EMS) alone or superimposed over voluntary contraction (EV) can effectively improve muscle strength. However, the effect of this type of training on the ability to control force production at submaximal levels is unknown. The authors examined the effects of EV training on steadiness in force production of knee extensors and flexors in older adults. Forty participants, including 20 men and 20 women, 60-77 years of age, were randomly allocated into a control group (CG) and an electromyostimulation superimposed over voluntary contraction (EVG) group. The EVG performed 30 bilateral isometric knee extension and flexion contractions per session, 3 training sessions per week, for 6 weeks. The variations in force production, expressed in absolute (standard deviation [SD]) and relative (coefficient of variation [CV]) terms, were assessed in isometric contractions at 5%, 15% and 25% maximal voluntary contraction (MVC) levels. Results indicated that MVC increased in knee extension and flexion in EVG (p < .05) after the training; steadiness CV also improved at 15% MVC in knee flexion (p < .05) but no significant changes were found in knee extension and steadiness SD. The training-induced changes in MVC were not correlated to steadiness CV that might indicate different mechanisms underlying these adaptations.  相似文献   
92.
The present study had two aims: First, to investigate the joint and specific roles of working memory (WM) and intelligence as predictors of school achievement. And second, to replicate and extend earlier findings (Spinath, Spinath, Harlaar, & Plomin, 2006) on the incremental validity of non-cognitive over cognitive abilities in the prediction of school achievement. The present sample consisted of N = 179 Chinese primary school children in the fourth grade. All measures including working memory (WM), intelligence and motivational items were assessed in class. Teachers provided test scores for the domains of Chinese and Math. We found that WM was a good predictor of school achievement and comparable in predictive power to intelligence. Together, cognitive ability including both WM and intelligence explained 17.8% and 36.4% of the variance in children's Chinese and Math scores, respectively. The relative importance of WM and intelligence varied with school domains with greater predictive power of WM for Math while intelligence explained a greater proportion of the variance in Chinese although the magnitude of this difference was only moderate. Domain-specific motivational constructs contributed only marginally to the prediction of school achievement for both Chinese and Math.  相似文献   
93.
校园欺凌现象在全球范围普遍存在,为有效解决校园欺凌问题,研究一采用《特拉华校园受欺凌量表》、《简易应对方式量表》以及《社会情绪健康量表》对416名5~6年级小学生进行了调查,结果发现,小学生消极应对方式可以显著预测校园受欺凌,社会情绪能力在消极应对方式与校园受欺凌中起调节作用。此基础上,研究二开展基于社会情绪能力的校园受欺凌团体辅导干预研究。结果表明,社会情绪能力的提升可以显著降低校园受欺凌水平。  相似文献   
94.
Given the prevalence of imagery appeals in today’s marketplace, the current research studies the role of mental imagery in how consumers process and react to advertisements with different numbers of ad claims. Past research has proposed “three” as the magical number of ad claims that maximizes persuasion, with more than three ad claims increasing skepticism and reducing evaluation. In the current research, we replicate this so-called “charm of three” effect, but only when consumers do not engage in mental imagery; when they do, however, we find that the effect is moderated, in that more ad claims beyond three produces more favorable product evaluation. Additionally, we provide evidence that the moderating effect of mental imagery is driven by transportation and skepticism toward the ad claims, with mental imagery increasing transportation and decreasing skepticism when there are more than three ad claims. Our research contributes to a better understanding of the “charm of three” effect, its boundary conditions, and underlying mechanism.  相似文献   
95.
Xu  Xiaofeng  Nie  Qingqing  Liu  Wang  Huebner  E. Scott  Tian  Lili 《Journal of Happiness Studies》2022,23(6):2805-2826

Life satisfaction is a key indicator of children’s healthy development. Although the developmental changes of life satisfaction during adolescence have been investigated, the developmental trajectories of life satisfaction and related predictors during childhood remain unclear. Thus, the current study aimed to identify the developmental trajectories of life satisfaction covering the period from middle to late childhood as well as to examine the predictive roles of environmental factors (i.e., family dysfunction and basic psychological needs satisfaction at school), personality factors (i.e., neuroticism and extraversion), and their interactions in these developmental trajectories. An accelerated longitudinal design was used with Chinese elementary school students (N?=?1069, 45.8% girls, M age?=?9.43, SD?=?0.95) of 3 cohorts (grade 3, grade 4, and grade 5) on 4 occasions at 6-month intervals. Growth mixture modeling analyses revealed three distinct trajectories of life satisfaction: “High-Stable” (88.8%), “High-Decreasing” (6.8%), and “Low-Increasing” (4.4%). Multivariate logistic regression analyses revealed that family dysfunction and neuroticism served as risk factors for adverse developmental trajectories of life satisfaction; whereas basic psychological needs satisfaction at school served as a protective factor. Furthermore, the interaction between family dysfunction and extraversion suggested that higher levels of extraversion buffered children against the negative effect of family dysfunction on the development of life satisfaction. The identification of three heterogeneous trajectory groups of children’s life satisfaction and key personality and environmental predictors associated with the trajectories suggests that specific interventions need to be tailored to the unique characteristics of the relevant trajectory groups.

  相似文献   
96.
执行功能缺陷是网络成瘾发生、维持和复发的原因之一,以往研究侧重于探讨网络成瘾者注意控制、反应抑制等执行功能成分的损伤状况,而其记忆抑制状况尚不清楚。本研究通过考察网络成瘾大学生的提取诱发遗忘(RIF)来探讨其记忆抑制的特点及RIF的产生机制。结果发现:低网络成瘾个体在高项目竞争强度下表现出显著的RIF,在低项目竞争强度下未产生;高网络成瘾个体在低项目竞争强度下表现出显著的RIF,在高项目竞争强度下未产生。结果表明网络成瘾大学生的记忆抑制能力受损严重,其在低项目竞争强度下易受相关代价与效益问题(CCB)影响而产生干扰性RIF。  相似文献   
97.
In the family‐based prevention science literature, family functioning, defined as positive parenting, parental involvement, family cohesion, family communication, parental monitoring of peers, and parent–adolescent communication, has been shown to ameliorate HIV risk behaviors in Hispanic youth. However, the majority of studies have relied solely on parent or adolescent reports and we know very little about parent–adolescent family functioning discrepancies. Therefore, the purpose of this study was to examine whether and to what extent parent–adolescent discrepancies in family functioning increased the risk of HIV risk behaviors, including substance use and sexual risk behaviors, and whether these associations vary as a function of acculturation and youth gender. A total of 746 Hispanic 8th grade youth and their primary caregivers were included in the study. Structural equation modeling findings indicate that parent–adolescent family functioning discrepancies are associated with an increased risk of Hispanic adolescent HIV risk behaviors, including lifetime and past 90‐day alcohol and illicit drug use, and early sex initiation. In addition, study findings indicate that results vary by acculturation and youth gender. Findings are discussed in the context of existing family‐based research and practice in preventing and reducing HIV risk behaviors among Hispanic youth and their families.  相似文献   
98.
Abundant research conducted in Western contexts has shown that biological risk factors such as low resting heart rate (HR) might be related to childhood aggression. However, it was unclear (1) how resting HR, as well as other markers of cardiac functions such as resting vagal tone, may be related to subtypes of aggression such as reactive and proactive aggression, and (2) whether the HR-aggression relation can be replicated in non-Western contexts. Therefore, this study examined the concurrent and prospective relations between resting HR, vagal tone, and Chinese children’s reactive and proactive aggression. Participants were 183 children (M age?=?7.64 years, 91 girls) recruited from an elementary school in Zhenjiang, PRC. Children’s resting HR and vagal tone were assessed in the second grade (T1). Teachers rated children’s reactive and proactive aggression in the second (T1) and fourth grade (T2). Results showed that lower resting HR at T1 was associated with higher reactive and proactive aggression at T1 and T2, and higher vagal tone was associated with lower HR, which in turn was related to higher reactive and proactive aggression at T1 and T2. Lower vagal tone was directly related to higher reactive but not proactive aggression at T1 and T2, whereas lower HR was related to higher reactive aggression at T2 for children with low or moderate vagal tone but was not for children with high vagal tone. These psychophysiological findings from a non-Western context add additional support for both similarities and differences between reactive and proactive aggression in childhood.  相似文献   
99.
The purpose of this study was to examine whether anxious shyness and regulated shyness, initially identified in the Chinese culture, is found in South Korean children, and to explore whether these two forms of shyness were differentially related to children's psychosocial functioning. Participants were 544 fourth to sixth grade children (251 girls, M age = 11.38 years old) who were recruited from an elementary school in Bucheon City, South Korea. Children's anxious and regulated shyness were measured using peers' nominations and teachers' ratings, whereas their social preference and social impact were assessed using peers' nominations. Parents rated their children's temperamental shyness and effortful control, and children self‐reported their loneliness and interpersonal concerns. The results of confirmatory factor analysis replicated the two factor model of shyness found in previous studies of Chinese children. Anxious shyness and regulated shyness were positively associated and were similarly related to temperamental shyness. Anxious shyness was negatively related to effortful control and social preference, and positively associated with self‐reported loneliness and interpersonal concerns, whereas regulated shyness was positively related to effortful control and social preference and negatively associated with loneliness and social impact. These results were generally consistent with prior Chinese findings and provided preliminary support for the construct validity of anxious and regulated shyness in another Asian culture that emphasizes interdependence and modesty. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
100.
随着人们对于肿瘤性疾病的发生、发展、转移机制的进一步探索,循环肿瘤细胞(CTCs)逐渐进入人们视野,其应用价值日益体现,可用于肿瘤性疾病的早期诊断及治疗效果的监测,尤其是对于早期肿瘤的诊断具有独特优势。其富集技术及检测方法也在发生着日新月异的变化。近年来,微流控分析芯片技术运用于 CTCs 的富集及检测,具有高丰度、高富集度、高活性及不需要对样本进行预处理等优点使得人们聚焦于此技术,本文对微流控分析芯片在 CTCs 检测中的运用做简要综述。  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