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   8889篇
  免费   113篇
  国内免费   6篇
教育   5881篇
科学研究   1078篇
各国文化   322篇
体育   705篇
综合类   4篇
文化理论   62篇
信息传播   956篇
  2021年   84篇
  2020年   121篇
  2019年   170篇
  2018年   211篇
  2017年   238篇
  2016年   214篇
  2015年   143篇
  2014年   180篇
  2013年   1599篇
  2012年   189篇
  2011年   189篇
  2010年   169篇
  2009年   172篇
  2008年   228篇
  2007年   210篇
  2006年   176篇
  2005年   164篇
  2004年   176篇
  2003年   118篇
  2002年   110篇
  2001年   149篇
  2000年   170篇
  1999年   148篇
  1998年   77篇
  1997年   76篇
  1996年   71篇
  1994年   64篇
  1993年   74篇
  1992年   132篇
  1991年   133篇
  1990年   141篇
  1989年   152篇
  1988年   113篇
  1987年   109篇
  1986年   113篇
  1985年   149篇
  1984年   120篇
  1983年   101篇
  1982年   92篇
  1981年   73篇
  1980年   80篇
  1979年   128篇
  1978年   82篇
  1977年   80篇
  1976年   74篇
  1975年   62篇
  1974年   84篇
  1973年   72篇
  1971年   69篇
  1968年   64篇
排序方式: 共有9008条查询结果,搜索用时 15 毫秒
1.
Grit has been defined as passionate perseverance toward long-term challenging goals and it is associated with various positive outcomes for youth, including academic achievement. However, less is known about these associations for the two facets of grit (i.e., perseverance of effort, consistency of interest) and few studies have examined the link between grit and perceived social support. The present study examined the group-level demographic differences (i.e., gender, grade, socioeconomic status, and special education status) of grit in a high school sample (N = 1,077). In addition, direct associations between grit and perceived social support from multiple sources (i.e., teacher, classmate, parent) were examined, as well as a potential enhancing effect of social support as a moderator of the relation between grit and academic achievement. Results indicated positive associations among grit and its facets with social support from parents and classmates. Furthermore, the positive relation between grit and achievement was stronger for students reporting high social support from teachers, but not other sources (i.e., classmates, parents). Practical and theoretical implications for promoting student success are discussed.  相似文献   
2.
As the research base for school crisis intervention and prevention expands, the need for well-developed tools to assess school readiness in the event of a crisis increases. This paper describes how the Comprehensive Crisis Plan Checklist (CCPC) was updated to reflect advances in crisis management and crisis planning. An extensive literature search and pilot study were used to refine existing items and create new items for the checklist. The Comprehensive Crisis Plan Checklist, 2nd Edition (CCPC-2) has 102 items separated into three sections: prevention, intervention, and postvention. The CCPC-2 can be used by crisis teams to create new crisis plans or evaluate existing ones. Users are encouraged to carefully consider the inclusion of all items and articulate why individual items are not necessarily based on their specific needs. The CCPC-2 was given to 10 pairs of raters to evaluate school-based crisis plans; average interrater reliability was 89.04%. Discussion focuses on item analysis and how to use the checklist within a school setting.  相似文献   
3.
4.
Four experiments show that 4- and 5-year-olds (total N = 112) can identify the referent of underdetermined utterances through their Naïve Utility Calculus—an intuitive theory of people’s behavior structured around an assumption that agents maximize utilities. In Experiments 1–2, a puppet asked for help without specifying to whom she was talking (“Can you help me?”). In Experiments 3–4, a puppet asked the child to pass an object without specifying what she wanted (“Can you pass me that one?”). Children’s responses suggest that they considered cost trade-offs between the members in the interaction. These findings add to a body of work showing that reference resolution is informed by commonsense psychology from early in childhood.  相似文献   
5.
BackgroundConsidering the potential cumulative effects of repetitive head impact (HI) exposure, we need sensitive biomarkers to track short- and long-term effects. Circulating small extracellular vesicles (sEVs) (<200 nm) traffic biological molecules throughout the body and may have diagnostic value as biomarkers for disease. The purpose of this study was to identify the microRNA (miRNA) profile in circulating sEVs derived from human plasma following repetitive HI exposure.MethodsHealthy adult (aged 18–35 years) soccer players were randomly assigned to one of 3 groups: the HI group performed 10 standing headers, the leg impact group performed 10 soccer ball trapping maneuvers over 10 min, and the control group did not participate in any soccer drills. Plasma was collected before testing and 24 h afterward, and sEVs were isolated and characterized via nanoparticle tracking analysis. Next-generation sequencing was utilized to identify candidate miRNAs isolated from sEVs, and candidate microRNAs were analyzed via quantitative polymerase chain reaction. In silico target prediction was performed using TargetScan (Version 7.0; targetscan.org) and miRWalk (http://mirwalk.umm.uni-heidelberg.de/) programs, and target validation was performed using luciferase reporter vectors with a miR-7844-5p mimic in human embryonic kidney (HEK) 293T/17 cells.ResultsPlasma sEV concentration and size were not affected across time and group following repetitive HI exposure. After 24 h, the HI read count from next-generation sequencing showed a 4-fold or greater increase in miR-92b-5p, miR-423-5p, and miR-24-3p and a 3-fold or greater decrease in miR-7844-5p, miR-144-5p, miR-221-5p, and miR-22-3p. Analysis of quantitative polymerase chain reaction revealed that leg impact did not alter the candidate miRNA levels. To our knowledge, miR-7844-5p is a previously unknown miRNA. We identified 8 miR-7844-5p mRNA targets: protein phosphatase 1 regulatory inhibitor subunit 1B (PPP1R1B), LIM and senescent cell antigen-like domains 1 (LIMS1), autophagy-related 12 (ATG12), microtubule-associated protein 1 light chain 3 beta (MAP1LC3B), integrin subunit alpha-1 (ITGA1), mitogen-activated protein kinase 1 (MAPK1), glycogen synthase kinase 3β (GSK3β), and mitogen-activated protein kinase 8 (MAPK8).ConclusionCollectively, these data indicate repetitive HI exposure alters plasma sEV miRNA content, but not sEV size or number. Furthermore, for the first time we demonstrate that previously unknown miR-7844-5p targets mRNAs known to be involved in mitochondrial apoptosis, autophagy regulation, mood disorders, and neurodegenerative disease.  相似文献   
6.
Editorial     
B. Sury 《Resonance》2018,23(7):723-725
  相似文献   
7.
ABSTRACT

This article offers a textual analysis and semiotic reading of the Rich Kids of Tehran's (RKOT’s) Instagram page. Contributing to scholarship on Iranian youth media practices, this article interrogates how the RKOT navigate urban and rural space to engage in everyday processes of resistance against global and local systemic oppression. Grounding their visual representations on Instagram in historical and cultural context, the author questions how and when quotidian actions are transformed into political transgressions when posted on social media. This article emphasizes the RKOT's agency in shaping their brand by analyzing representations of gender performance, intertextuality, and national identity on Instagram.  相似文献   
8.
This study seeks to understand the emotional connection of teachers' academically productive talk (APT) with student learning from the students' perspective. Using a sample of 2,225 students (N7th grade = 1,146 and N8th grade = 1,079) from 16 middle schools in a city of China, we investigate the relationship between students' perceptions of their teachers’ APT, student emotions (enjoyment and anxiety) and their discursive engagement with others in the mathematics classroom. Results from structural equation modelling and mediation analysis show that after controlling for gender, family resources and mathematics achievement, student-perceived teacher APT was positively associated with their discursive engagement with classmates. Furthermore, student enjoyment and anxiety in class mediated the relationship between student-perceived teacher APT and student discursive engagement with classmates. Multi-group analysis revealed that the model was invariant across genders and grades, indicating that the associations were applicable to male and female students as well as to seventh and eighth graders. These findings shed light on the emotional relationship of teacher APT with the discursive engagement of their students. Although prior research observes a positive relationship between teacher productive classroom talk and student discursive engagement primarily through classroom observations and teacher reflections, this study provides evidence from the students’ perspective and highlights the mediating role of student emotions in the relationship.  相似文献   
9.
The lower limb kinetics of curve sprinting in amputees are not well described in the literature, particularly with respect to the effect of the side of amputation. This is an issue due to the importance of the knowledge for prosthetic design and classification of athletes. Thus, the aim of this study was to investigate the influence of side of amputation on curve sprinting performance in athletes with a unilateral leg amputation. A three-dimensional motion analysis system (Vicon), four force plates (Kistler) and a modified mathematical human model (ALASKA) were used to compare clockwise and counter clockwise curve sprinting lower limb kinematics and kinetics of a Paralympic medalist with a left-sided knee exarticular amputation. Results reveal that vertical ground reaction force application and total vertical impulse were lower when the affected limb was at the inside of the curve. The unaffected limb showed joint mechanics different to those established for non-amputee athletes and might contribute better to propulsion when being the inside limb. Curve sprinting biomechanics and the ability to attain high radial velocities are directly dependent on the side of amputation relative to the curve direction in a unilateral amputee athlete of highest performance level.  相似文献   
10.
Research remains unclear on the impact of physiological load on perceptual-cognitive skills in sport. Moreover, no study has examined the training of perceptual-cognitive skills under physiological load. The current study comprised two phases. Firstly, we examined the impact of badminton-specific physiological load on anticipatory skills in expert badminton players (n = 13), including key underlying mechanisms, such as gaze behaviour. Under high physiological load, participants displayed less efficient visual search behaviour and showed a reduction in response accuracy. Secondly, we examined the effects of combining perceptual-cognitive simulation training with the high physiological load. Ten of the expert badminton players were assigned to a combined training group, where the simulation training and the physiological load intervention occurred simultaneously or an independent training group, whereby the two components were completed independently. The combined training group showed a positive change in the efficiency of their visual search behaviours compared to the independent training group, but no significant performance improvements were found. Overall, findings demonstrate that high physiological load is detrimental to experts’ anticipatory skills. However, combining perceptual-cognitive simulation training with high physiological load can potentially negate these debilitating effects.  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