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   436篇
  免费   6篇
教育   338篇
科学研究   18篇
各国文化   3篇
体育   47篇
文化理论   6篇
信息传播   30篇
  2023年   2篇
  2022年   10篇
  2021年   9篇
  2020年   14篇
  2019年   22篇
  2018年   24篇
  2017年   27篇
  2016年   18篇
  2015年   11篇
  2014年   25篇
  2013年   75篇
  2012年   24篇
  2011年   21篇
  2010年   24篇
  2009年   14篇
  2008年   12篇
  2007年   14篇
  2006年   10篇
  2005年   8篇
  2004年   10篇
  2003年   8篇
  2002年   8篇
  2001年   6篇
  2000年   3篇
  1999年   7篇
  1998年   2篇
  1997年   5篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   3篇
  1991年   1篇
  1990年   4篇
  1989年   1篇
  1987年   2篇
  1985年   2篇
  1984年   3篇
  1981年   1篇
  1978年   3篇
  1977年   1篇
  1976年   1篇
  1975年   2篇
  1938年   1篇
排序方式: 共有442条查询结果,搜索用时 15 毫秒
111.
The purpose of this paper is to review ten actions that can be taken by multi- disciplinary child protection teams or individuals in this field to assure that the interests of the abused child are consistently addressed.  相似文献   
112.
The results of previous cross-section studies suggest that childhood hearing impairment may lead to parental psychosocial stress. The present study investigated whether modifications in parental psychic state can be ascertained in connection with the child's treatment events and the child's hearing and speech status, in a prospective study design. Data were available on 116 fathers and mothers regarding the pre-cochlear implant examination or hearing aid fitting of their child. In the course of the child's treatment, parental quality of life improved from a low to a normal level. Among children who were at the stage of pre-examination for a cochlear implant, better hearing and speech capacity was linked to more severe impairment of the parental state. It is emphasized that the parents whose children showed comparatively good language development at the time of pre-examination for a cochlear implant were especially subjected to stress.  相似文献   
113.
114.
This paper uses a unique data set of Mexican researchers to explore the determinants of research output and impact. Our findings confirm a quadratic relationship between age and the number of published papers. However, publishing peaks when researchers are approximately 53 years old, 5 or 10 years later than what prior studies have shown. Overall, the results suggest that age does not have a substantial influence on research output and impact. We also find that reputation matters for the number of citations but not publications. Results also show important heterogeneity across areas of knowledge. Interpretations of other aspects, such as gender, country of PhD, and cohort effect, among others, are also discussed.  相似文献   
115.

Introduction

Glycolysis affects glucose determination in vitro. The placement of sample tubes in ice-water slurry with plasma separation within 30 minutes is recommended, or alternatively the use of a glycolysis inhibitor. The aim of our two-steps study was to evaluate which Terumo tube is best for glucose determination in routine clinical setting.

Materials and methods

In the first study, blood from 100 volunteers was collected into lithium heparin (LH), NaF/Na heparin (FH) and NaF/citrate buffer/Na2EDTA (FC-Mixture) tubes. LH sample was treated as recommended and considered as reference, while FH and FC-Mixture samples were aliquoted, maintained at room temperature (RT) for 1, 2 and 4 hours; centrifuged and plasma analysed in triplicate. In the second study, samples from 375 volunteers were collected in LH, FH and FC-Mixture tubes and held at RT before centrifugation from 10 to 340 minutes, depending on each laboratory practice. Samples were analysed in one analytical run.

Results

In the first study, FH glucose concentrations were 5.15 ± 0.66 mmol/L, 5.05 ± 0.65 mmol/L and 5.00 ± 0.65 mmol/L (P < 0.001) in tubes stored at RT for 1, 2 and 4 hours, respectively. Mean biases in all time points exceeded the analytical goal for desirable bias based on biological variation criteria. FC-Mixture glucose concentrations were 5.48 ± 0.65 mmol/L, 5.46 ± 0.6 mmol/L and 5.46 ± 0.64 mmol/L in tubes stored at RT for 1, 2 and 4 hours, respectively. Mean biases for FC-Mixture glucose in all time points reached optimal analytical goals. In the second study, the biases for LH and FH glucose compared to reference FC-Mixture glucose exceeded the preset analytical goals, regardless of the blood collection to centrifugation time interval.

Conclusions

FC-mixture tubes glucose concentrations were preserved up to 4h storage at RT. We confirmed that NaF alone does not allow immediate glycolysis inhibition in real life pre-centrifugation storage conditions (up to 340 minutes). FC-Mixture should be used exclusively for glucose determination in laboratories unable to implement the recommended blood samples’ treatment.Key words: glucose, pre-analytical phase, sodium fluoride, citrate acidification, stability  相似文献   
116.
An electronic portfolio system, designed to serve as a resource-based learning space, was tested in a fifth-grade science class. The control-group students accessed a traditional folder-based information display in the system and the experimental-group students accessed a concept map-based information display to review a science portfolio. The student-constructed science portfolio was a result of a collection of digital artefacts such as graphic images, instructional videos and textual files on terms and definitions relevant to the Earth's atmosphere. In the information-processing performance test, the experimental-group students scored significantly higher and spent much less time in finding answers to the questions presented. Also, in the 3-day delayed memory retention tests, the experimental-group students achieved significantly higher scores. The multiple regression models confirm that the visualisation variation is the most significant predictor for student performance (ie, comprehension and access time). Also, the regression models suggest that language-arts proficiency may reduce overall system access time; while higher math proficiency may predict retention scores.  相似文献   
117.
In this study we investigated junior high school students' processes of argumentation and cognitive development in science and socioscientific lessons. Detailed studies of the relationship between argumentation and the development of scientific knowledge are rare. Using video and audio documents of small group and classroom discussions, the quality and frequency of students' argumentation was analyzed using a schema based on the work of Toulmin ( 1958 ). In parallel, students' development and use of scientific knowledge was also investigated, drawing on a schema for determining the content and level of abstraction of students' meaning‐making. These two complementary analyses enabled an exploration of their impact on each other. The microanalysis of student discourse showed that: (a) when engaging in argumentation students draw on their prior experiences and knowledge; (b) such activity enables students to consolidate their existing knowledge and elaborate their science understanding at relatively high levels of abstraction. The results also suggest that students can acquire a higher quality of argumentation that consists of well‐grounded knowledge with a relatively low level of abstraction. The findings further suggest that the main indicator of whether or not a high quality of argument is likely to be attained is students' familiarity and understanding of the content of the task. The major implication of this work for developing argumentation in the classroom is the need to consider the nature and extent of students' content‐specific experiences and knowledge prior to asking them to engage in argumentation. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 45: 101–131, 2008  相似文献   
118.
This longitudinal study investigates the differences in cognitive and socio‐emotional development and academic achievement between children educated in special education classes (N = 37) and regular classes (N = 37). The study is retrospective. The first measurement point was while children were attending play‐oriented kindergarten and no decision about their education had yet been made. The second measurement point followed after 2 years of schooling. Comparing carefully matched groups, no differences in executive functions (EFs) were found before beginning school. Children assigned to special education had poorer language, fine motor skills and a lower pre‐academic self‐concept, self‐regulatory skills and social integration. Notably, every fourth child in special education was an immigrant, 9% of whom later attended regular classes. After 2 years of schooling in either setting, the groups differed significantly in academic achievement, EFs, fine motor skills and cognitive self‐regulatory skills. However, it was not – as school officials had intended – that children in special education classes had caught up, except in regard to their academic self‐concept and social integration.  相似文献   
119.
120.
Literacy is a human right unequally distributed among the world's population. Despite global efforts to fight illiteracy, high illiteracy rates continue to jeopardize access for many to basic schooling, life-long learning, health, and environment safety. Illiteracy also hinders the economic prosperity of the poorest societies in this digital age. Among the underserved population in Latin America, many of the indigenous children are the poorest of the poor who hardly have access to formal and stable schooling. This paper reviews the literature addressing education inequality issues in Latin America and possible opportunities with mobile learning technology to counter the effects of the education inequality. Also, this paper suggests mobile technology design considerations to meet the particular learning needs of the extremely underserved and underachieving indigenous children in Latin America.  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