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   272篇
  免费   3篇
教育   230篇
科学研究   18篇
体育   12篇
文化理论   2篇
信息传播   13篇
  2023年   4篇
  2022年   3篇
  2021年   5篇
  2020年   7篇
  2019年   8篇
  2018年   7篇
  2017年   6篇
  2016年   7篇
  2015年   11篇
  2014年   6篇
  2013年   67篇
  2012年   6篇
  2011年   3篇
  2010年   9篇
  2009年   6篇
  2007年   4篇
  2006年   6篇
  2004年   7篇
  2003年   5篇
  2002年   6篇
  2001年   3篇
  2000年   3篇
  1999年   7篇
  1998年   4篇
  1997年   3篇
  1996年   6篇
  1994年   3篇
  1993年   3篇
  1992年   2篇
  1990年   3篇
  1989年   2篇
  1984年   3篇
  1983年   1篇
  1982年   4篇
  1981年   3篇
  1980年   1篇
  1979年   3篇
  1978年   6篇
  1977年   3篇
  1976年   3篇
  1975年   3篇
  1974年   4篇
  1973年   3篇
  1972年   2篇
  1967年   1篇
  1959年   1篇
  1958年   1篇
  1928年   1篇
  1927年   1篇
  1926年   2篇
排序方式: 共有275条查询结果,搜索用时 15 毫秒
51.
The controversy over what is an appropriate early childhood curriculum has created a need for research instruments designed to measure classroom practices. This article reports on the development of a new observational measure based on the Guidelines for Developmentally Appropriate Practices of the National Association for the Education of Young Children (NAEYC). The Classroom Practices Inventory (CPI) is a 26-item rating scale tapping the curricular emphasis and emotional climate of programs for 4- and 5-year-old children. The scale demonstrated a high degree of internal consistency. Over half the measure's variance was accounted for by a factor tapping encouragement of curiosity, creativity, and provision of concrete materials. In a study of 10 preschool programs, CPI scores correlated significantly with teachers' and parents' educational attitudes. Modest relationships were found between the CPI scores of children's preschools and measures of academic skills, creativity, and anxiety. The CPI appears to be a promising measure for critically examining the concept of developmentally appropriate practices in early childhood education.  相似文献   
52.
Selection medium is important in sperm isolation for assisted reproductive technologies. Contrary to the naturally occurring human cervical mucus which has a high viscosity, most current practices for motility based sperm selection use a low viscosity medium. In this study, we used a microfluidic device to assess the effects of high viscosity media made with hyaluronic acid (HA) and methyl cellulose (MC) on bovine and human sperm motility and viability (sperm transferred directly from cryoprotectant). The microfluidic penetration test, viability, and motility were compared for sperm swimming in both HA and MC media with about 20cp viscosity (measured at 20 °C). Our resulted indicate that MC medium resulted in a significantly higher number of viable bovine sperm penetrating the medium as compared to HA. Furthermore, MC resulted in the selection of a sperm subpopulation with a 274% increase in sperm viability in comparison to the raw semen, while HA increased viability by only 133%. In addition to viability, bovine sperm motility parameters were significantly higher in the MC medium as compared with HA. Experiments with human sperm swimming in MC indicate that sperm swim slower and straighter at higher viscosities. In conclusion, the results indicate that in a micro-confined environment representative of the in vivo environment, MC is a preferred high viscosity medium to ensure the highest concentration of motile and viable sperm.  相似文献   
53.

Introduction

Vaspin (visceral adipose tissue-derived serpin) was first described as an insulin-sensitizing adipose tissue hormone. Recently its anti-inflammatory function has been demonstrated. Since no appropriate data is available yet, we sought to investigate the plasma concentrations of vaspin in sepsis.

Materials and methods

57 patients in intensive care, fulfilling the ACCP/SCCM criteria for sepsis, were prospectively included in our exploratory study. The control group consisted of 48 critically ill patients, receiving intensive care after trauma or major surgery. Patients were matched by age, sex, weight and existence of diabetes before statistical analysis. Blood samples were collected on the day of diagnosis. Vaspin plasma concentrations were measured using a commercially available enzyme-linked immunosorbent assay.

Results

Vaspin concentrations were significantly higher in septic patients compared to the control group (0.3 (0.1-0.4) ng/mL vs. 0.1 (0.0-0.3) ng/mL, respectively; P < 0.001). Vaspin concentration showed weak positive correlation with concentration of C-reactive protein (CRP) (r = 0.31, P = 0.002) as well as with SAPS II (r = 0.34, P = 0.002) and maximum of SOFA (r = 0.39, P < 0.001) scoring systems, as tested for the overall study population.

Conclusion

In the sepsis group, vaspin plasma concentration was about three-fold as high as in the median surgical control group. We demonstrated a weak positive correlation between vaspin and CRP concentration, as well as with two scoring systems commonly used in intensive care settings. Although there seems to be some connection between vaspin and inflammation, its role in human sepsis needs to be evaluated further.Key words: adipocytokine, inflammation, vaspin, CRP, intensive care  相似文献   
54.
55.
56.
57.
The drying shrinkage accumulation from exposure of freshly prepared gesso layers to relative humidity (RH) cycles was determined to elucidate the mechanism of craquelure pattern formation on panel paintings. The progresive drying shrinkage of the gesso is observed only under the cycles going to high RH levels which bring about transitions from brittle to ductile state of the material. The first incidence of fracture on the gesso layers occurred after a limited number of cycles ranging between a few and 100 for a range of layer thickness between 0.5 and 1?mm. The craquelure patterns stabilised also after a limited number of cycles (30 for the 1-mm thick layer). Upon increase in the gesso layer thickness, the strength of the layer is reduced and the spacing of shrinkage fractures increases. The study demonstrated that craquelure patterns, mimicking historical ones, can be realistically produced in laboratory conditions. Such studies would provide useful information for preparing specimens simulating historic panel paintings and would inform the current efforts on automatic, computer-aided classifications of crack formations on paintings.  相似文献   
58.
59.
The purpose of this research was to explore trainer questioning strategies which aimed to scaffold development and learning in teacher training feedback sessions. Research was conducted with a group of Turkish pre-service English teacher trainees at an English-medium university in Turkey. Findings include a categorisation of different question types which seemed to prompt reflection and construction of knowledge. The data also suggest that trainees need varying levels of support through different question types to better scaffold their understanding of teaching. This study concludes with a data-driven framework of questioning strategies which can be a potential guide for trainers working with pre-service English teacher trainees.  相似文献   
60.
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