全文获取类型
收费全文 | 36778篇 |
免费 | 389篇 |
国内免费 | 14篇 |
专业分类
教育 | 26901篇 |
科学研究 | 3208篇 |
各国文化 | 292篇 |
体育 | 2677篇 |
综合类 | 8篇 |
文化理论 | 579篇 |
信息传播 | 3516篇 |
出版年
2021年 | 258篇 |
2020年 | 426篇 |
2019年 | 637篇 |
2018年 | 2917篇 |
2017年 | 2828篇 |
2016年 | 2339篇 |
2015年 | 614篇 |
2014年 | 744篇 |
2013年 | 4749篇 |
2012年 | 782篇 |
2011年 | 1360篇 |
2010年 | 1301篇 |
2009年 | 910篇 |
2008年 | 1172篇 |
2007年 | 1633篇 |
2006年 | 515篇 |
2005年 | 770篇 |
2004年 | 880篇 |
2003年 | 709篇 |
2002年 | 487篇 |
2001年 | 477篇 |
2000年 | 554篇 |
1999年 | 449篇 |
1998年 | 268篇 |
1997年 | 280篇 |
1996年 | 324篇 |
1995年 | 256篇 |
1994年 | 269篇 |
1993年 | 225篇 |
1992年 | 354篇 |
1991年 | 380篇 |
1990年 | 342篇 |
1989年 | 367篇 |
1988年 | 337篇 |
1987年 | 328篇 |
1986年 | 327篇 |
1985年 | 374篇 |
1984年 | 296篇 |
1983年 | 304篇 |
1982年 | 241篇 |
1981年 | 250篇 |
1980年 | 261篇 |
1979年 | 349篇 |
1978年 | 260篇 |
1977年 | 239篇 |
1976年 | 200篇 |
1975年 | 181篇 |
1974年 | 182篇 |
1973年 | 177篇 |
1971年 | 175篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
871.
872.
This study examines the organizational characteristics of 51 higher education institutions in relationship to student performance and growth. The study first finds that organizational measures of mission, size, wealth, complexity, and selectivity are statistically represented by the 2-year versus 4-year college mission. Findings indicate that 2-year and 4-year campuses indeed do exert significantly different influences on undergraduate GPA and self-reported intellectual growth. Next, the study uses both OLS regression and HLM to examine these influences. High school percentile rank and college classroom experiences are better predictors of Cum GPA at 4-year institutions, while student effort is a better predictor of GPA at 2-year institutions. Whereas the most important predictors of Cum GPA include precollege measures such as high school percentile rank and SAT score, the most influential predictors of student intellectual growth are campus experiences including classroom vitality, peer support, student effort, commitment, and involvement. Controlling for all other variables, students at 2-year institutions receive higher grades, and students at 4-year campuses experience more growth. 相似文献
873.
The results of recent studies into the use of the concept mapping heuristic seem to demonstrate that meaningful learning results through its use in science classrooms. While this underscores the need to use more effective instructional strategies in science teaching, the issue of the intervening variable of anxiety in learning and science achievement, and the possible use of a metacognitive strategy in anxiety reduction have not been addressed. This study, therefore, sought to find out if the metacognitive strategy of concept mapping reduces anxiety and thereby enhances achievement in biology. A total of 51 (30 boys, 21 girls) senior secondary one (grade 10) students participated in this experiment. Two instruments—the Zuckerman Affect Adjective Checklist and the Biology Achievement Test—were used in pre- and posttest administrations to measure the treatment effect on anxiety and achievement, respectively. Findings support the stand that concept mapping is significantly more effective than the traditional/expository teaching strategy in enhancing learning in biology. In addition, it apparently reduces students' anxiety towards the learning of biology. A significant reduction of anxiety was noticed for male subjects. 相似文献
874.
Jane Kohlhoff David J. Hawes Melanie Mence Alex M. T. Russell Lucinda Wedgwood Susan Morgan 《Parenting, science and practice》2016,16(4):302-319
Objective. This study examined the cognitive-affective strategies used by parents of young children with conduct problems to regulate emotions. Key questions concerned the extent to which these emotion regulation strategies are associated with positive and negative parenting practices and predict quality of parenting through interplay with parental depression. Design. Participants were families of toddlers (n = 84) referred to a tertiary-level health service for the treatment of disruptive behavior problems. Parenting practices were indexed through observational coding of parent–child interactions and self-report data on multiple dimensions of positive and negative parenting. Parents self-reported their use of cognitive reappraisal and expressive suppression—the two emotion regulation strategies that are most robustly associated with psychosocial functioning in adults. Results. Associations between emotion regulation strategy and quality of parenting were moderated by parental depressive symptom severity, with distinct effects seen for positive and negative parenting practices. In terms of positive parenting, more frequent use of cognitive reappraisal was associated with increased use of labeled praise among parents with lower levels of depressive symptoms, whereas parents who had higher levels of depressive symptoms engaged in less such praise regardless of how frequently they used reappraisal. In terms of negative parenting, frequent use of cognitive reappraisal and expression suppression were associated with reduced levels of negative parenting, but only among parents with high levels of depression. Conclusions. These findings add to growing support for the integration of emotion regulation strategies into family process models of early-onset conduct problems and related clinical interventions. 相似文献
875.
The big upper bound of typical van der Waerden number was investigated through calculating the van der Waerden number on a circle. And the van der Waerden number Wh (3,3) = 9, Wh (3,3,3)≥25 on a circle was calculated by computer. 相似文献
876.
Perception of sign language and its application to visual communications for deaf people 总被引:1,自引:0,他引:1
Video communication systems for deaf people are limited in terms of quality and performance. Analysis of visual attention mechanisms for sign language may enable optimization of video coding systems for deaf users. Eye-movement tracking experiments were conducted with profoundly deaf volunteers while watching sign language video clips. Deaf people are found to fixate mostly on the facial region of the signer to pick up small detailed movements associated with facial expression and mouth shapes. Lower resolution, peripheral vision is used to process information from larger, rapid movements of the signer in the video clips. A coding scheme that gives priority to the face of the signer may be applied to improve perception of video quality for sign language communication. 相似文献
877.
Pauline?A.?Porcaro Denise?E.?Jackson Patricia?M.?McLaughlin Cindy?J.?O’MalleyEmail authorView authors OrcID profile 《Journal of Science Education and Technology》2016,25(3):345-357
A common trend in higher education is the “flipped” classroom, which facilitates active learning during class. The flipped approach to teaching was instituted in a haematology ‘major’ class and the students’ attitudes and preferences for the teaching materials were surveyed. The curriculum design was explicit and involved four major components (1) the preparation of the students; (2) the weekly pre-class work; (3) the in-class active learning strategies and (4) closing the learning loop using formative quizzes. Each of these components is discussed in detail and was informed by sound pedagogical strategies. Several different sources of information and several freely available software tools to engage the students are discussed. Two iterations are reported here, with improved pass rate for the final examination from 47 to 48 % in the traditional class to 56–65 % in the flipped classroom approach. The majority of students (93 and 89 %) came to the class prepared, after viewing the screencasts and engaged fully with the activities within the face-to-face time. The students perceived that solving case studies (93 %) was the most beneficial activity for their learning and this was closely followed by the production of essay plans (71 %). The majority of students recommended that this approach be repeated the following year (69 and 75 %). 相似文献
878.
A Methylome‐Wide Association Study of Trajectories of Oppositional Defiant Behaviors and Biological Overlap With Attention Deficit Hyperactivity Disorder
下载免费PDF全文
![点击此处可从《Child development》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Edward D. Barker Esther Walton Charlotte A.M. Cecil Richard Rowe Sara R. Jaffee Barbara Maughan Thomas G. O'Connor Argyris Stringaris Alan J. Meehan Wendy McArdle Caroline L. Relton Tom R. Gaunt 《Child development》2018,89(5):1839-1855
In 671 mother–child (49% male) pairs from an epidemiological birth cohort, we investigated (a) prospective associations between DNA methylation (at birth) and trajectories (ages 7–13) of oppositional defiant disorder (ODD), and the ODD subdimensions of irritable and headstrong; (b) common biological pathways, indexed by DNA methylation, between ODD trajectories and attention deficit hyperactivity disorder (ADHD); (c) genetic influence on DNA methylation; and (d) prenatal risk exposure associations. Methylome‐wide significant associations were identified for the ODD and headstrong, but not for irritable. Overlap analysis indicated biological correlates between ODD, headstrong, and ADHD. DNA methylation in ODD and headstrong was (to a degree) genetically influenced. DNA methylation associated with prenatal risk exposures of maternal anxiety (headstrong) and cigarette smoking (ODD and headstrong). 相似文献
879.
Child Development and the Social Demography of Childhood 总被引:1,自引:0,他引:1
Donald J. Hernandez 《Child development》1997,68(1):149-169
This article provides background information and a practical guide for including demographic information in developmental research. First, it portrays historic demographic trends reflecting critical ways in which the family and economic environments of children have been, and continue to be, transformed in the United States. Second, it presents current demographic statistics to provide a basis for researchers to compare their special study population to the general population of children and to formulate specific hypotheses about ways in which their result might differ for children in various demographic situations. Third, it offers an Appendix with standardized wording for a minimum set of questions needed to measure the demographic characteristics and environments of children. The Appendix provides researchers the technical capacity to collect such data, so they can develop and test hypotheses about how family and econmic environments shape child development processes and outcomes. 相似文献
880.
Very few studies have examined issues of work-life balance among faculty of different racial/ethnic backgrounds. Utilizing data from Harvard University’s Collaborative on Academic Careers in Higher Education project, this study examined predictors of work-life balance for 2953 faculty members from 69 institutions. The final sample consisted of 1059 (36%) Asian American faculty, 512 (17%) African American faculty, 359 (12%) Latina/o faculty, and 1023 (35%) White/Caucasian faculty. There were 1184 (40%) women faculty and 1769 (60%) men faculty. The predictors of worklife balance included faculty characteristics, departmental/institutional characteristics and support, and faculty satisfaction with work. While African American women faculty reported less work-life balance than African American men, the reverse was true for Latina/o faculty. In addition, White faculty who were single with no children were significantly less likely to report having work-life balance than their married counterparts with children. Faculty rank was a significant positive predictor of work-life balance for all faculty. Notably, the findings highlight the importance of department and institutional support for making personal/family obligations and an academic career compatible. Institutional support for making personal/family obligations and an academic career compatible was consistently the strongest positive predictor of perceived work-life balance for all faculty. In addition, satisfaction with time spent on research had positive associations with work-life balance for all faculty, highlighting how faculty from all racial/ethnic backgrounds value being able to spend enough time on their own research. 相似文献