全文获取类型
收费全文 | 467篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
教育 | 299篇 |
科学研究 | 85篇 |
各国文化 | 2篇 |
体育 | 49篇 |
综合类 | 5篇 |
文化理论 | 4篇 |
信息传播 | 28篇 |
出版年
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 15篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 16篇 |
2013年 | 67篇 |
2012年 | 16篇 |
2011年 | 23篇 |
2010年 | 10篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 16篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 11篇 |
2001年 | 16篇 |
2000年 | 5篇 |
1999年 | 10篇 |
1998年 | 12篇 |
1997年 | 8篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1992年 | 5篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1967年 | 2篇 |
1960年 | 2篇 |
1957年 | 2篇 |
1947年 | 2篇 |
1934年 | 2篇 |
排序方式: 共有472条查询结果,搜索用时 46 毫秒
1.
U. Casellato F. Fenzi P. Guerriero S. Sitran P. A. Vigato U. Russo M. Galgani M. Mendera A. Manasse 《Journal of Cultural Heritage》2003,4(4):337-353
A significant number of archaeological finds of the 13th–16th century from the Tuscan sites of Germagnana and Gambassi in Valdelsa—FI, was studied by different physico-chemical investigations (SEM–EDS, ICP, Mössbauer spectroscopy, XRD, XRF, TG-DTA) in order to contribute to clarify the production methodology and the pre-industrial glass manufacture technology. The studied samples are mainly non-vitreous finds as production waste, refractory materials, crucibles and raw materials; also vitreous finds as frits, skims, glasses (glass masses, glass working waste and finished products) have been taken into consideration. The obtained petrographic and physico-chemical data strongly suggest that both Gambassi and Germagnana glass manufactures were strictly connected with the sources of vitrifiable materials, situated in Tuscan sand quarries. In particular a comparison between sands from the neighbouring quarries and appropriate finds of the two archaeological sites evidences that the employed vitrifiable materials possibly belong to La Casina La Cava resort. The archaeological classification, based on macroscopic observation and stratigraphic position, was compared and verified with the scientific classification of the examined finds of Germagnana and Gambassi sites based on their composition, morphology and physico-chemical properties. 相似文献
2.
Understanding the Information Needs of Academic Scholars in Agricultural and Biological Sciences 总被引:4,自引:0,他引:4
This study investigates the information needs of faculty and graduate students in agricultural and biological sciences. Qualitative research methods, interviews and focus groups, were used to examine what types of information these scholars need for their research, teaching and learning, how they seek that information, and perceptions. The implications for library service are discussed. 相似文献
3.
There is a crisis of valuation practices in the current academic life sciences, triggered by unsustainable growth and “hyper-competition.” Quantitative metrics in evaluating researchers are seen as replacing deeper considerations of the quality and novelty of work, as well as substantive care for the societal implications of research. Junior researchers are frequently mentioned as those most strongly affected by these dynamics. However, their own perceptions of these issues are much less frequently considered. This paper aims at contributing to a better understanding of the interplay between how research is valued and how young researchers learn to live, work and produce knowledge within academia. We thus analyze how PhD students and postdocs in the Austrian life sciences ascribe worth to people, objects and practices as they talk about their own present and future lives in research. We draw on literature from the field of valuation studies and its interest in how actors refer to different forms of valuation to account for their actions. We explore how young researchers are socialized into different valuation practices in different stages of their growing into science. Introducing the concept of “regimes of valuation” we show that PhD students relate to a wider evaluative repertoire while postdocs base their decisions on one dominant regime of valuing research. In conclusion, we discuss the implications of these findings for the epistemic and social development of the life sciences, and for other scientific fields. 相似文献
4.
Objective: To determine the effective nucleotide sites of ribozymes against HCV, and obtain a highly effective, nontoxic and
inexpensive antisense ribozyme specific for HCV. Methods: Two effective ribozymes, targeted to HCV 5’NC region and C region,
were designed and synthesized. Eukaryotic expression vectors, pSV2-gpt. CD-SR (, containing either HCRZNC or HCRZC were constructued
and transfected into MT-2 cells, which had been infected by HCV. Quantitative PCR and hydridization were used to determine
the effect of inhibition of HCV by ribozymes. Results: HCRZNC and HCRZC suppressed the replication of HCV by 54.7% and 62.1%,
respectively. Furthermore, when both ribozymes were cotransfected into cells, they suppressed replication by 78.8%. Conclusion:
Two specific antisense ribozymes have strong inhibitory effects on the replication of HCV in cultured cells, and have better
effect when used together. 相似文献
5.
6.
7.
本首先分析了当前我国专科教育所面临的发展困境与成因,进而提出了改革我国专科教育体制、建立新型专科教育运行机制的构想与相关的政策性建议。作认为,作为高等教育的一个重要组成部分,专科教育为我国的社会主义教育事业作了重要贡献,但目前又进入到一个新的发展转型期,挑战与发展的机遇关存;改革计划管理的约束的体制,寻求办学效益和社会效益的统一,建立起与社会主义市场经济体制相适应的专科教育体制与机制,实现教育体制与学校功能的战略性调整,是现阶段专科教育改革发展的必然趋势和重要条件。 相似文献
8.
John U. Ogbu 《The Urban Review》1995,27(3):189-205
Culture has featured prominently in minority educational research, policies, and intervention since the early 1960s. It is
receiving even more attention today in minority education discourse due to the emergence of cultural diversity and multicultural
education as popular national issues. A careful analysis of the new discourse suggests, however, that the issue has shifted
from how cultural differences enhance or deter the school adjustment and academic performance of minority children to the
problem of cultural hegemony and representation in school curriculum and other domains of education. But cultural diversity
and multicultural education are only a partial solution to the problems of culture in minority education. This essay is in
two parts. In part one I argue for a reconsideration of the earlier question about how culture affects minority school adjustment
and academic performance. I also proposecultural frame of reference as a new level of analysis of the cultural problems that confront minority students at school. In part two I illustrate my
points with two case studies from Minority Education Project in Oakland, California. 相似文献
9.
G. M. Sankolli M. I. Khatkhatay M. P. Desai D. K. Pardhe P. C. Ishrad U. M. Joshi 《Indian journal of clinical biochemistry : IJCB》1992,7(1):71-74
Aprototype kit for the detection of occurrence of ovulation based on urinary pregnanediol glucuronide estimations by ELISA
was developed in our laboratory. This kit was sent for evaluation at 4 centres in Bombay and Pune, India. The diagnosis of
ovulation/anovulation based on the results of the kit is comparable with that based on reference parameters commonly used
(ultrasonography of ovarian follicles and serum progesterone estimations). The accuracy of the test was 93.5%, specificity
was 87.5% and sensitivity was 95.7%. This rapid indigenous test can be very useful in assessing ovulatory status of the woman
by the clinicians in their offices. 相似文献
10.
Proteins and glutathione (GSH) levels were estimated in the experimental groups. Levels of both proteins and glutathione in
the control and the treated groups were found to be significantly decreased compared to the normal group. The results show
that supplementation of riboflavin has beneficial effect by alleviating the oxidant injuries to GSH and proteins, which are
involved in the maintenance of transparency and protection of thiol groups of the lens. Thus, riboflavin has an active role
in the lens metabolism and has a potential to improve the metabolic activity of the cataractous lenses. 相似文献