全文获取类型
收费全文 | 1802篇 |
免费 | 12篇 |
国内免费 | 10篇 |
专业分类
教育 | 1104篇 |
科学研究 | 164篇 |
各国文化 | 6篇 |
体育 | 398篇 |
综合类 | 10篇 |
文化理论 | 6篇 |
信息传播 | 136篇 |
出版年
2024年 | 3篇 |
2023年 | 17篇 |
2022年 | 9篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 9篇 |
2014年 | 45篇 |
2013年 | 31篇 |
2012年 | 134篇 |
2011年 | 183篇 |
2010年 | 93篇 |
2009年 | 50篇 |
2008年 | 135篇 |
2007年 | 155篇 |
2006年 | 150篇 |
2005年 | 105篇 |
2004年 | 91篇 |
2003年 | 74篇 |
2002年 | 67篇 |
2001年 | 61篇 |
2000年 | 62篇 |
1999年 | 52篇 |
1998年 | 16篇 |
1997年 | 29篇 |
1996年 | 21篇 |
1995年 | 37篇 |
1994年 | 18篇 |
1993年 | 9篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 15篇 |
1989年 | 13篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 15篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1959年 | 3篇 |
1958年 | 5篇 |
1957年 | 3篇 |
1956年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有1824条查询结果,搜索用时 296 毫秒
51.
WOMBAT A tool for mixed model analyses in quantitative genetics by restricted maximum likelihood (REML) 总被引:31,自引:0,他引:31
Meyer K 《Journal of Zhejiang University. Science. B》2007,8(11):815-821
WOMBAT is a software package for quantitative genetic analyses of continuous traits, fitting a linear, mixed model; estimates of covariance components and the resulting genetic parameters are obtained by restricted maximum likelihood. A wide range of models, comprising numerous traits, multiple fixed and random effects, selected genetic covariance structures, random regression models and reduced rank estimation are accommodated. WOMBAT employs up-to-date numerical and computational methods. Together with the use of efficient compilers, this generates fast executable programs, suitable for large scale analyses. Use of WOMBAT is illustrated for a bivariate analysis. The package consists of the executable program, available for LINUX and WINDOWS environments, manual and a set of worked example, and can be downloaded free of charge from http://agbu. une.edu.au/~kmeyer/wombat.html 相似文献
52.
Pushpendra KG Harindra SB Pawan LK Neeraj K Ajay K Reyazul RM Amita M Jitendra K 《Journal of Zhejiang University. Science. B》2007,8(11):807-814
Quantitative trait loci (QTL) analysis was conducted in bread wheat for 14 important traits utilizing data from four different mapping populations involving different approaches of QTL analysis. Analysis for grain protein content (GPC) sug- gested that the major part of genetic variation for this trait is due to environmental interactions. In contrast, pre-harvest sprouting tolerance (PHST) was controlled mainly by main effect QTL (M-QTL) with very little genetic variation due to environmental interactions; a major QTL for PHST was detected on chromosome arm 3AL. For grain weight, one QTL each was detected on chromosome arms 1AS, 2BS and 7AS. QTL for 4 growth related traits taken together detected by different methods ranged from 37 to 40; nine QTL that were detected by single-locus as well as two-locus analyses were all M-QTL. Similarly, single-locus and two-locus QTL analyses for seven yield and yield contributing traits in two populations respectively allowed detection of 25 and 50 QTL by composite interval mapping (CIM), 16 and 25 QTL by multiple-trait composite interval mapping (MCIM) and 38 and 37 QTL by two-locus analyses. These studies should prove useful in QTL cloning and wheat improvement through marker aided selection. 相似文献
53.
Teachers' education, classroom quality, and young children's academic skills: results from seven studies of preschool programs 总被引:10,自引:0,他引:10
Early DM Maxwell KL Burchinal M Alva S Bender RH Bryant D Cai K Clifford RM Ebanks C Griffin JA Henry GT Howes C Iriondo-Perez J Jeon HJ Mashburn AJ Peisner-Feinberg E Pianta RC Vandergrift N Zill N 《Child development》2007,78(2):558-580
In an effort to provide high-quality preschool education, policymakers are increasingly requiring public preschool teachers to have at least a Bachelor's degree, preferably in early childhood education. Seven major studies of early care and education were used to predict classroom quality and children's academic outcomes from the educational attainment and major of teachers of 4-year-olds. The findings indicate largely null or contradictory associations, indicating that policies focused solely on increasing teachers' education will not suffice for improving classroom quality or maximizing children's academic gains. Instead, raising the effectiveness of early childhood education likely will require a broad range of professional development activities and supports targeted toward teachers' interactions with children. 相似文献
54.
Subtypes, severity, and structural stability of peer victimization: what does latent class analysis say? 总被引:2,自引:1,他引:1
This study uses latent class analysis (LCA) to empirically identify victimization groups during middle school. Approximately 2,000 urban, public middle school students (mean age in sixth grade = 11.57) reported on their peer victimization during the Fall and Spring semesters of their sixth, seventh, and eighth grades. Independent LCA analyses at each semester yielded 3 victim classes based on victimization degree rather than type (e.g., physical vs. relational). The most victimized class always represented the smallest proportion of the sample, decreasing from 20% in sixth grade to 6% by the end of eighth grade. This victimized class also always reported feeling less safe at school concurrently and more depressed than others 1 semester later, illustrating the validity of the LCA approach. 相似文献
55.
Stability in cardiac indicators before birth and their utility in predicting variation in postnatal development were examined. Fetal heart rate and variability were measured longitudinally from 20 through 38 weeks gestation (n = 137) and again at age 2 (n = 79). Significant within-individual stability during the prenatal period and into childhood was demonstrated. Fetal heart rate variability at or after 28 weeks gestation and steeper developmental trajectories were significantly associated with mental and psychomotor development at 2 years (n = 82) and language ability at 2.5 years (n = 61). These data suggest that the foundations of individual differences in autonomic control originate during gestation and the developmental momentum of the fetal period continues after birth. 相似文献
56.
Parish-Morris J Hennon EA Hirsh-Pasek K Golinkoff RM Tager-Flusberg H 《Child development》2007,78(4):1265-1287
To what extent do children with autism (AD) versus typically developing children (TD) rely on attentional and intentional cues to learn words? Four experiments compared 17 AD children (M age=5.08 years) with 17 language- and 17 mental-age-matched TD children (M ages=2.57 and 3.12 years, respectively) on nonverbal enactment and word-learning tasks. Results revealed variability in all groups, but particularly within the AD group. Performance on intention tasks was the most powerful predictor of vocabulary in the AD group but not in the TD groups. These findings suggest that word learning cannot be explained exclusively by either attentional or intentional processes, and they provide evidence of a special role for intentional understanding in the vocabulary development of AD children. 相似文献
57.
Cognitive processes associated with child neglect 总被引:1,自引:0,他引:1
OBJECTIVE: To compare neglectful and non-neglectful mothers on information processing tasks related to child emotions, behaviors, the caregiving relationship, and recall of child-related information. METHOD: A natural group design was used. Neglectful mothers (N=34) were chosen from active, chronic caseloads; non-neglectful comparison mothers (N=33) were obtained from community agencies serving families. Participants were administered the IFEEL Picture task to assess maternal perceptions of infant emotions, eight vignettes of young children's behavior to assess attributions for child behavior across different scenarios, and a passage recall task to assess information processing problems. A measure of depression was used as a covariate to control for this variable. RESULTS: Neglectful mothers were significantly less likely to recognize infants' feelings of interest, more likely to see sadness and shame, more inaccurate at labeling infants' emotions, and had a more limited emotion vocabulary. They also made more internal and stable attributions for children's behaviors in situations where it was not clear whether a child was at risk of harm, and had poor recall of information. Depressive symptoms had little effect on these findings with the exception of information recall. CONCLUSIONS: Neglectful mothers show significant problems in information processing concerning their child's emotions and behaviors, which may affect their childrearing behavior. Cognitive-behavioral interventions to improve parents' abilities to recognize their child's emotions and to address maladaptive attributions may be of value. 相似文献
58.
Duggan A Caldera D Rodriguez K Burrell L Rohde C Crowne SS 《Child abuse & neglect》2007,31(8):801-827
OBJECTIVES: To assess the impact of a voluntary, paraprofessional home visiting program in preventing child maltreatment and reducing the multiple, malleable psychosocial risks for maltreatment for which families had been targeted. METHODS: This collaborative, experimental study focused on 6 Healthy Families Alaska (HFAK) programs; 325 families were enrolled in 2000-2001, randomized to intervention and control groups, and interviewed to measure baseline attributes. Follow-up data were collected when children were 2 years old (85% follow-up rate). Outcomes included maltreatment reports, measures of potential maltreatment and parental risks, for example, poor mental health, substance use, and partner violence. HFAK records were reviewed to measure home visiting services. Home visitors were surveyed to measure perceived effectiveness and training adequacy. RESULTS: Parental risks were common at baseline, and one-sixth of families had a substantiated child protective services report in the child's first 2 years of life. There was no overall program effect on maltreatment reports, and most measures of potential maltreatment. Home visited mothers reported using mild forms of physical discipline less often than control mothers. The groups were similar in their use of more severe forms of physical discipline. There was no program impact on parental risks. There was no impact on outcomes for families with a 'high dose' of home visiting. Home visitors often failed to address parental risks and seldom linked families with community resources. Contradictions in the model compromised effectiveness. CONCLUSIONS: The program did not prevent child maltreatment, nor reduce the parental risks that had made families eligible for service. Research is needed to develop and test strategies to improve the effectiveness of home visiting. 相似文献
59.
60.