全文获取类型
收费全文 | 4092篇 |
免费 | 46篇 |
国内免费 | 9篇 |
专业分类
教育 | 3009篇 |
科学研究 | 295篇 |
各国文化 | 71篇 |
体育 | 258篇 |
综合类 | 3篇 |
文化理论 | 25篇 |
信息传播 | 486篇 |
出版年
2023年 | 12篇 |
2022年 | 40篇 |
2021年 | 65篇 |
2020年 | 133篇 |
2019年 | 181篇 |
2018年 | 220篇 |
2017年 | 216篇 |
2016年 | 193篇 |
2015年 | 125篇 |
2014年 | 191篇 |
2013年 | 979篇 |
2012年 | 139篇 |
2011年 | 137篇 |
2010年 | 132篇 |
2009年 | 131篇 |
2008年 | 126篇 |
2007年 | 115篇 |
2006年 | 101篇 |
2005年 | 69篇 |
2004年 | 56篇 |
2003年 | 75篇 |
2002年 | 56篇 |
2001年 | 50篇 |
2000年 | 48篇 |
1999年 | 37篇 |
1998年 | 29篇 |
1997年 | 34篇 |
1996年 | 22篇 |
1995年 | 26篇 |
1994年 | 29篇 |
1993年 | 25篇 |
1992年 | 20篇 |
1991年 | 30篇 |
1990年 | 24篇 |
1989年 | 22篇 |
1988年 | 17篇 |
1987年 | 24篇 |
1986年 | 15篇 |
1985年 | 25篇 |
1984年 | 13篇 |
1983年 | 14篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1973年 | 8篇 |
1971年 | 8篇 |
排序方式: 共有4147条查询结果,搜索用时 0 毫秒
211.
Windsor J Benigno JP Wing CA Carroll PJ Koga SF Nelson CA Fox NA Zeanah CH 《Child development》2011,82(4):1040-1046
This report examines 174 young children's language outcomes in the Bucharest Early Intervention Project, the first randomized trial of foster placement after institutional care. Age of foster placement was highly correlated with language outcomes. Placement by 15 months led to similar expressive and receptive language test scores as typical age peers at 30 and 42 months. Placement from 15 to 24 months also led to dramatic language improvement. In contrast, children placed after 24 months had the same severe language delays as children in institutional care. Language samples at 42 months confirmed that placement after 24 months led to lower expressive skill. 相似文献
212.
213.
Children continue to be subjected to high levels of violence (i.e., physical, psychological and sexual maltreatment) throughout the world. International concern about violence against children has increased significantly during the last decade. A Study on Violence Against Children, encouraged by the UN Committee on the Rights of the Child, conducted under the auspices of the United Nations Secretary General and reported in 2006, has become a rallying call to improve child protection. Child protection practices and systems have been judged to be generally inadequate and, in some cases, destructive. It is widely recognized that business as usual—more of the same—will not do. A General Comment (guide to fulfilling obligations) for Article 19, the central conceptualization of child protection of the UN Convention on the Rights of the Child, has the potential to promote a worldwide reformulation of child protection priorities, policies, and practices by virtue of the infusion of a child rights approach. It can be a mechanism for framing and promoting the transformational change needed – for a genuine paradigm shift. Here, explication is given for the historical context, rationale, centrality of child rights, process of development, holistic nature, and primary elements of General Comment 13 (GC13): The child's right to freedom from all forms of violence. GC13 embodies and champions a child rights approach to child protection entailing strong support for proactive primary prevention, promotion of good child care, and a commitment to secure the rights and well-being of all children. A child rights-based, comprehensive coordinating framework is recommended for the implementation of GC13. 相似文献
214.
Objective
Young children involved with child welfare services are at high risk for behavior problems. This study aims to identify externalizing behavior paths that preschoolers in this high-risk population follow over a 6 year period, and the predictors of membership in normative and problematic pathways.Methods
Using data from the National Study of Child and Adolescent Well-being (NSCAW), the sample included 246 4-year-olds who remained home after investigation. Latent class growth analysis (LCGA) was used to estimate the number, size, and shape of subgroups of preschoolers following distinct behavioral pathways. Early predictors of membership in the resulting groups were then examined.Results
Four groups of preschool children following distinct behavior trajectories over 6 years were identified. Weighted results show that more than half (61%) of the children followed a low/normal problem behavior trajectory while just over one tenth (12%) were on a persistent high trajectory, remaining in the clinical range throughout the study. Improving (23%) and worsening (4%) problem behavior groups were also identified. Internalizing problems, attention problems, child ethnicity, and maltreatment type reported at age 4 predicted membership in the trajectory groups.Conclusions
Internalizing behavior problems and maltreatment type may distinguish preschool children who are more likely to experience worsening or persistent problematic externalizing behaviors from those likely to follow a normal behavior trajectory.Practice implications
Identifying early indicators of externalizing behavior problems and addressing them with evidence-based interventions to reduce negative behaviors may avert long-term negative outcomes. 相似文献215.
The successful encapsulation of human hepatocellular carcinoma (HepG2) cells would greatly assist a broad range of applications in tissue engineering. Due to the harsh conditions during standard chitosan fiber fabrication processes, encapsulation of HepG2 cells in chitosan fibers has been challenging. Here, we describe the successful wet-spinning of chitosan-alginate fibers using a coaxial flow microfluidic chip. We determined the optimal mixing conditions for generating chitosan-alginate fibers, including a 1:5 ratio of 2% (w∕w) water-soluble chitosan (WSC) solution to 2% (w∕w) alginate solution. Ratio including higher than 2% (w∕w) WSC solution increased aggregation throughout the mixture. By suspending cells in the WSC-alginate solution, we successfully fabricated HepG2 cell-laden fibers. The encapsulated HepG2 cells in the chitosan-alginate fibers were more viable than cells encapsulated in pure alginate fibers, suggesting that cross-linked chitosan provides a better environment for HepG2 cells than alginate alone. In addition, we found that the adhesion of HepG2 cells on the chitosan-alginate fiber is much better than that on the alginate fibers. 相似文献
216.
Microfluidic techniques have been recently developed for cell-based assays. In microfluidic systems, the objective is for these microenvironments to mimic in vivo surroundings. With advantageous characteristics such as optical transparency and the capability for automating protocols, different types of cells can be cultured, screened, and monitored in real time to systematically investigate their morphology and functions under well-controlled microenvironments in response to various stimuli. Recently, the study of stem cells using microfluidic platforms has attracted considerable interest. Even though stem cells have been studied extensively using bench-top systems, an understanding of their behavior in in vivo-like microenvironments which stimulate cell proliferation and differentiation is still lacking. In this paper, recent cell studies using microfluidic systems are first introduced. The various miniature systems for cell culture, sorting and isolation, and stimulation are then systematically reviewed. The main focus of this review is on papers published in recent years studying stem cells by using microfluidic technology. This review aims to provide experts in microfluidics an overview of various microfluidic systems for stem cell research. 相似文献
217.
The combined use of dry cooling (DC) system and dedicated ventilation (DV) system to decouple cool-ing and dehumidification process for energy efficiency was proposed for subtropical climates like Hong Kong. In this study, the energy performance and condensation risk of the use of DCDV system were examined by analyzing its ap-plication in a typical office building in Hong Kong. Through hour-by-hour simulation using actual equipment per-formance data and realistic building and system characteristics, it was found that with the use of DCDV system, the annual energy consumption could be reduced by 54%in comparison with the conventional system (constant air vol-ume with reheat system). In respect of condensation risk, it was found that the annual frequency of occurrence of con-densation on DC coil was 35 h. Additional simulations were conducted to examine the influence of different parame-ters on the condensation risk of DCDV system. Measures to ensure condensate-free on DC coil were also discussed. 相似文献
218.
近10年来,从终身教育的立法到各项政策的推广实施,韩国终身教育领域出现了前所未有的变化。2007年修正的韩国《终身教育法》的公布不仅明确了终身教育的范围,而且也使中央与地方的职责与权限更加明确,并通过重组力图建构更加完善且有效率的终身教育行政与财政支援体制。为了振兴终身教育,韩国大力开展了相应的支援计划:终身学习城市支援计划;终身学习账户制度;终身学习中心大学培育计划;终身教育专业人员的培养及其能力提升计划等。呈现的特点:一是国家相关政策的制定与引导是推进终身教育的根本动力.足够的经费和人力资源支撑是必要条件。二是注重整合各类教育资源,特别是在建立多样的终身教育机构和设施等平台的同时,也注重发挥学校教育的作用。三是实施面向全员并开展全程的终身教育,特别注重增加弱势群体的教育机会。这次修正不仅促进了各自治团体终身教育基础设施的建设,提升了社区网络的发展水平,而且还建立了将学习成果运用于地方的循环体系,促进了国民对终身教育的理解及参与,推动了韩国社会的协调发展。 相似文献
219.
Journal of Science Education and Technology - As data become more available and integrated into daily life, there has been growing interest in developing data science curricula for youth in... 相似文献
220.
Lee Sunmin Adair Jennifer Keys Payne Katherina A. Barry David 《Early Childhood Education Journal》2022,50(7):1083-1095
Early Childhood Education Journal - Young children’s ideas of fairness have been studied in a range of laboratory settings with findings that children see fairness as equal distribution of... 相似文献