全文获取类型
收费全文 | 11772篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
教育 | 9108篇 |
科学研究 | 1215篇 |
体育 | 365篇 |
文化理论 | 386篇 |
信息传播 | 707篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 16篇 |
2019年 | 24篇 |
2018年 | 2187篇 |
2017年 | 2090篇 |
2016年 | 1577篇 |
2015年 | 116篇 |
2014年 | 123篇 |
2013年 | 143篇 |
2012年 | 227篇 |
2011年 | 690篇 |
2010年 | 841篇 |
2009年 | 438篇 |
2008年 | 646篇 |
2007年 | 1149篇 |
2006年 | 73篇 |
2005年 | 393篇 |
2004年 | 449篇 |
2003年 | 357篇 |
2002年 | 129篇 |
2001年 | 11篇 |
2000年 | 21篇 |
1999年 | 3篇 |
1997年 | 17篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 4篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1940年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
CRABTREE Vincent P. AZORIN-PERIS Vincent ECHIADIS Angelos SMITH Peter R. 《浙江大学学报(A卷英文版)》2007,8(6):916-920
Objective: To study the regulation of blood pulse volume via photoplethysmography (PPG) signal detected from toe, while the lower limb is passively raised in different height positions. Methods: Use a modified non-invasive PPG technique to detect the blood pulse signal on toe with infrared (IR) photo sensor. A protocol consisting of two postures, i.e., supine and 45° reclining, was designed to conduct laboratory trial in this study. During the period of performing the protocol of these postures, the lower limb was passively raised from the heights of 10 cm to 60 cm randomly and individually with sponge blocks underneath the foot. Results: In the supine posture, the higher the foot was passively raised, the more the blood PPG signal decreased. In the 45° reclining posture, the blood PPG signal increased at the beginning and then decreased in the foot height position from 10 cm to 60 cm. In both postures the normalized AC signal changes significantly while the normalized DC signal changes little. Conclusion: The toe PPG signals can obviously indicate the regulated blood volume change with the designated postural procedures due to the heart level position. 相似文献
52.
Females are underrepresented in certain disciplines, which translates into their having less promising career outlooks and lower earnings. This study examines the effects of socio-economic status, academic performance, high school curriculum and involvement in extra-curricular activities, as well as self-efficacy for academic achievement on choices of academic disciplines by males and females. Disciplines are classified based on Holland’s theory of personality-based career development. Different models for categorical outcome variables are compared including: multinomial logit, nested logit, and mixed logit. Based on the findings presented here, first generation status leads to a greater likelihood of choosing engineering careers for males but not for females. Financial difficulties have a greater effect on selecting scientific fields than engineering fields by females. The opposite is true for males. Passing grades in calculus, quantitative test scores, and years of mathematics in high school as well as self-ratings of abilities to analyze quantitative problems and to use computing are positively associated with choice of engineering fields. 相似文献
53.
Eirini Geraniou 《Educational Studies in Mathematics》2010,73(3):281-296
This paper presents results of a longitudinal study in the transition to independent graduate studies in mathematics. The
analysis of the data collected from 24 students doing a PhD in mathematics revealed the existence of three transitional stages
within the PhD degree, namely Adjustment, Expertise and Articulation. The focus is on the first two transitional stages, since the data collection focused mainly on these. Based on the first
two transitional stages and the students’ ways of dealing with them, which were called ‘survival strategies’, three types
of students were identified. The importance of motivation for each transitional stage and the successful transition overall
are considered as well. 相似文献
54.
Vitallis Chikoko 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》2008,54(2):243-263
This paper reports on a study of the role of parent governors in five neighbouring rural primary schools in Zimbabwe. The study proposed that despite the presence of a legal decentralised school governance structure in which parents form the majority, they did not have the capacity to function effectively therein, and were still marginalised in school governance decision-making. Four areas of decision-making were investigated: school organisation; curriculum; employment and appraisal of teaching staff; and financial resources. Interviews were conducted with parent governors, school heads and teachers. Findings show that all the respondent groups perceived significant parental involvement in the area of school finances only. However, parents were perceived to lack the capacity to make decisions in all four areas. The study concludes that the role of parents in the running of schools in the country has not significantly grown from that of being school financiers and builders of infrastructure. Therefore, building school governance capacity among parents is necessary. 相似文献
55.
India seems to have the highest prevalence of osteoporosis. With growing awareness of osteoporosis and its impact on life
span especially in India, special attention is being paid to early detection, management and treatment of postmenopausal osteoporosis
in women. Measurement of BMD and osteocalcin are of value in estimating bone turnover rates. The aim of this study is (1)
to measure the specific, sensitive bone formation marker such as osteocalcin and BMD in postmenopausal osteoporosis women
and postmenopausal non-osteoporosis women; (2) the follow up study to evaluate the impact of specific antiresorptive therapy
(alendronate + calcium + vitamin D) regimen in postmenopausal osteoporosis by assaying osteocalcin and BMD. Sixty clinically
diagnosed postmenopausal osteoporosis patients and 60 normal subjects (postmenopausal non-osteoporosis women) were recruited
as control. Mean bone mineral density T score and Z score was significantly decreased (P < 0.001) in postmenopausal osteoporosis patients as compared to controls. Highly significant increase in the mean score of
BMD—T score and Z score from baseline to post therapy of 3 months was observed in postmenopausal osteoporosis women. Serum osteocalcin levels
were significantly increased (P < 0.001) as compared to control group. Serum osteocalcin levels were decreased significantly (P < 0.001) from baseline to post therapy of 3 months in postmenopausal osteoporosis women. BMD is the best quantifiable predictor
of osteoporotic fracture and osteocalcin is specific, sensitive, promising, currently used marker for better prognosis of
osteoporosis and for monitoring responses to antiresorptive therapy. 相似文献
56.
57.
With the availability of the whole genome sequence of Escherichia coli or Corynebacterium glutamicum, strategies for directed DNA manipulation have developed rapidly. DNA manipulation plays an important role in understanding the function of genes and in constructing novel engineering bacteria according to requirement. DNA manipulation involves modifying the autologous genes and expressing the heterogenous genes. Two alternative approaches, using electroporation linear DNA or recombinant suicide plasmid, allow a wide variety of DNA manipulation. However, the over-expression of the desired gene is generally executed via plasmid-mediation. The current review summarizes the common strategies used for genetically modifying E. coli and C. glutamicum genomes, and discusses the technical problem of multi-layered DNA manipulation. Strategies for gene over-expression via integrating into genome are proposed. This review is intended to be an accessible introduction to DNA manipulation within the bacterial genome for novices and a source of the latest experimental information for experienced investigators. 相似文献
58.
Jie Yuan Sarah Carr Guosheng Ding Shimin Fu John Xuexin Zhang 《Reading and writing》2017,30(3):631-651
Prolonged inspection of a Chinese character induces a feeling of uncertainty of the character, a phenomenon named as Orthographic Satiation. However, there has not been direct evidence showing that such satiation does occur at the orthographic level. To investigate whether Chinese satiation occurs at the orthographic level or at other levels, the present study applies a speeded repetition priming paradigm to Chinese, which has been successfully used to examine Semantic Satiation in English. When judging whether a category name matched an exemplar word, participants showed gradually slower responses as the character standing for the category name was repeated, indicating the occurrence of satiation. However, repetition of a character without accessing its meaning, or repeated access to its meaning without repeating the character itself, did not elicit satiation. The results suggest Orthographic Satiation occurs not at the orthographic level, but at a level associating orthography and meaning during Chinese character reading. 相似文献
59.
Aisi LI 《Frontiers of Education in China》2014,9(2):188-210
The foundation of Shanxi University is a prime example of the collaborative efforts in higher education between the Chinese and British in late Qing China (1842–1912). Both sides made compromises, with the Chinese adapting their ideas of educational sovereignty, and the British agreeing to work under the supervision of the local government. Such a collaboration was made possible by the individual personalities of the two founders and their visions for China’s higher education. The dual structure of the university, with one department to teach Chinese learning and the other to teach Western learning, showed that, at a local and personal level, these officials and missionaries opted for direct cooperation, despite the myriad changes and upheavals following the Boxer Movement. In addition, by allowing foreign missionaries into critical roles in a government university, the principle of ti-yong dualism was gradually being adapted. The formation of Shanxi University not only demonstrates the dynamics of the Sino-Western educational relationship and the roles individuals played in it, but also stimulates reflection on China’s contemporary cross-border partnerships in higher education 相似文献
60.