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   11632篇
  免费   0篇
教育   8967篇
科学研究   1217篇
体育   365篇
文化理论   388篇
信息传播   695篇
  2022年   2篇
  2019年   6篇
  2018年   2180篇
  2017年   2077篇
  2016年   1567篇
  2015年   107篇
  2014年   115篇
  2013年   87篇
  2012年   221篇
  2011年   693篇
  2010年   837篇
  2009年   434篇
  2008年   645篇
  2007年   1154篇
  2006年   71篇
  2005年   393篇
  2004年   445篇
  2003年   355篇
  2002年   136篇
  2001年   7篇
  2000年   21篇
  1999年   2篇
  1997年   16篇
  1995年   5篇
  1993年   2篇
  1991年   9篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1985年   2篇
  1984年   5篇
  1983年   3篇
  1982年   1篇
  1981年   1篇
  1979年   3篇
  1977年   2篇
  1976年   1篇
  1973年   1篇
  1969年   1篇
  1968年   2篇
  1967年   2篇
  1966年   1篇
  1965年   1篇
  1964年   1篇
  1963年   2篇
  1959年   1篇
  1892年   3篇
  1885年   1篇
  1840年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
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   
62.
63.
The contemporary era provides several challenges which extend from the reconstitution of an innovative knowledge domain and curricula to candidate learning platforms that support online course delivery methods. Educators and scholars on these demands have recently started to rethink alternative ways for the assimilation of the experiential knowledge in three-dimensional (3D) technologically advanced environments, like 3D multi-user virtual worlds. In spite the widespread dissemination and proliferation of novel educational implications by utilizing 3D multi-user virtual worlds combined with the 2D interface of LMS (Learning Management Systems) and the assessment of the effectiveness based on the online course delivery method in a long-term usability is still absent from the international academic literature. This study presents interoperability issues focused on the utilization of the virtual world Open Simulator (Open Sim) in conjunction with Sloodle (Simulation Linked Object Oriented Dynamic Learning Environment) as a free plug-in module. The evaluation of this online learning process according to an empirical research method became possible with the assistance of ninety-five (95) students by two different academic sectors that participated in this project and measured the capabilities and instructional affordances of this platform. The evaluation process was focused on four multi-dimensional parameters (psychological-pedagogical, technical-operational, organizational-financial, and socio-cultural). The study findings based on students’ experiences revealed that both platforms could be sufficiently connected as a unique platform which can increase the users’ learning abilities. This “hybrid” platform can adequately convert the ordinary multi-user virtual world of Open Sim and Sloodle in a common “incubator” of knowledge for online courses at university level. At the end, the instructional affordances and implications for future-driven directions are also discussed.  相似文献   
64.
This paper explores the internationalization of higher education initiatives of Hong Kong, being one of the Special Administrative Regions (SAR) of China, within the context of the Chinese Mainland-Hong Kong (CM-HK) relations. Historical, social, economic, and political ties between Hong Kong and the Mainland of China, their economic and political interdependency, and a time series analysis of Hong Kong’s University Grants Committee (UGC) statistical data (local and non-local participation, geographic composition, and cost analysis of UGC-funded programs) are used to support what the author calls the “intra-nationalization of higher education.” This forms a unique internationalization strategy, whereby a sub-national region such as Hong Kong and possibly Macau, orients its internationalization strategy towards a motherland, in this case China.  相似文献   
65.
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   
66.
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   
67.
This paper reports the asymmetric synthesis of an important pharmaceutical intermediate (3S)-1-[(1R)-2-hydroxy-1-phenylethyl]-3-methylpiperidin-2-one (compound 1) from commercially available D-plenylglycinol and delta-valerolactone. During the alkylation process, the hydroxyl group can be protected or unprotected, resulting in a different consumption of s-BuLi, and leading to a different diastereomeric excess (de) of compound 1. When 1-[(1R)-2-hydroxy-1-phenylethyl]-piperidin-2-one (compound 2) was alkylated with 2.5 eq. of s-BuLi, compound 1 was obtained as a single isomer detected by chiral high performance liquid chromatography (HPLC) columns with an overall yield of 91%. With the hydroxyl group protected, (R)-1-(2-[(tert-butyldimethylsil) oxy]-1-phenylethyl) piperidine-2-one (compound 6) could be alkylated with 1.5 eq. of s-BuLi, giving compound 1 and its diastereoisomer 8 in a ratio of 1:2.5 and a yield of methylation of 90%. Compounds 1 and 8 could be separated completely and easily by flash chromatography. The absolute configuration of compound 8 was determined by singlecrystal X-ray analysis. The mechanism of the alkylation process is discussed based on experimental results.  相似文献   
68.
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   
69.
70.
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