全文获取类型
收费全文 | 541篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
教育 | 245篇 |
科学研究 | 258篇 |
各国文化 | 3篇 |
体育 | 2篇 |
文化理论 | 3篇 |
信息传播 | 33篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 20篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 36篇 |
2017年 | 25篇 |
2016年 | 24篇 |
2015年 | 29篇 |
2014年 | 28篇 |
2013年 | 53篇 |
2012年 | 16篇 |
2011年 | 19篇 |
2010年 | 24篇 |
2009年 | 28篇 |
2008年 | 23篇 |
2007年 | 17篇 |
2006年 | 29篇 |
2005年 | 21篇 |
2004年 | 15篇 |
2003年 | 24篇 |
2002年 | 10篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有544条查询结果,搜索用时 31 毫秒
131.
132.
133.
134.
From an instrumental view, conceptual frameworks that are carefully assembled from existing literature in Educational Technology and related disciplines can help students structure all aspects of inquiry. In this article we detail how the development of a conceptual framework that connects theory, practice and method is scaffolded and facilitated in an online doctoral program in Educational Technology. For online professional practice students, conceptual frameworks provide a lens to critically examine experiential knowledge and a solid foundation for the implementation of interdisciplinary research at a distance from their university campus and faculty mentors. 相似文献
135.
Amrita Chaudhary Pradeep Kumar Vandana Rai 《Indian journal of clinical biochemistry : IJCB》2021,36(3):257
Catechol-O-methyl transferase (COMT) enzyme catalyzes the metabolism of dopamine and other catechols in the brain. Several articles investigated catechol-O-methyltransferase (COMT) Val158Met polymorphism as risk factor for alcohol dependence (AD) but the results were inconclusive. The aim of present meta-analysis was to evaluate the association of Val158Met (COMT) polymorphism with AD. Authors performed keyword search of the 4 electronic databases—Pubmed, Google Scholar, Springer Link and Science Direct databases up to December 31, 2019. Total eighteen studies that investigated the association of Val158Met polymorphism with AD were retrieved. The pooled results from the meta-analysis (2278 AD cases and 3717 healthy controls) did not show association with AD using all 5 genetic models (allele contrast model: OR = 1.02, 95% CI = 0.90–1.14, p = 0.03; homozygote model: OR = 1.06, 95% CI = 0.81–1.38, p = 0.69; dominant model: OR = 0.99, 95% CI = 0.85–1.14, p = 0.87; co-dominant model: OR = 0.97, 95% CI = 0.86–1.11, p = 0.71; recessive model: OR = 1.05;95% CI = 0.85–1.29, p = 0.61). Results of subgroup analysis showed that Val158Met is not risk for AD in Asian and Caucasian population. In conclusion, COMT Val158Met is not a risk factor for alcohol dependence. 相似文献
136.
Anshita Aggarwal Sant Ram Abhilasha Garg Rimesh Pal Anil Bhansali Priyanka Singh Sadhna Sharma J. S. Thakur Naresh Sachdeva Sanjay Kumar Bhadada 《Indian journal of clinical biochemistry : IJCB》2021,36(1):67
We aimed to estimate metabolic bone profile in a large cohort of healthy, adult Indian population to generate reference standards of serum calcium, phosphate and alkaline phosphatase (ALP), 25 (OH) Vitamin D and iPTH, and also to find out the prevalence of Vitamin D deficiency in healthy population. Apparently healthy people in the age group of 20–80 years, residing in the union territory of Chandigarh were chosen. Fasting samples for serum calcium, phosphate, albumin, alkaline phosphatase (ALP), 25 (OH) D and iPTH were collected and were processed on the same day. We recruited 930 healthy subjects from different subsectors of Chandigarh. Final analysis was done for 915 subjects. Out of this, 530 (58%) were women and 385 (42%) were men. The study participants were divided into two groups, less than and more than 50 years for the men and pre and post-menopausal for the women. The serum calcium, phosphate, ALP and iPTH were significantly higher in the post-menopausal women compared to the pre-menopausal women. The median plasma 25 (OH) D in men and women was 12.5 ng/mL and 14.3 ng/mL, respectively. 25 (OH) D deficiency was seen in 65.4% of individuals. 25 (OH) D levels co-related negatively with iPTH levels (r = − 0.4, p < 0.0001), and showed an increasing trend with age. We have thus presented metabolic bone profile of healthy, adult north Indian population. These reference values can be used for diagnosis and monitoring of various MBDs. Vitamin D deficiency is still rampant in our population in spite of increasing awareness. 相似文献
137.
Government webportals are central to governments' web strategy. They are designed to be nodal hubs, or gateways, for encountering government, and as such position government in the online world. Yet the designs of government webportals, particularly their location within wider web ecologies are scarcely studied. In additional to these web ecologies, this paper conceptualises webportals as being located within wider information and institutional ecologies. Methodologically, it comparatively examines the hyperlink structures of the national government webportals of the top ten e-government countries: Australia; Canada; Finland; France; Japan; Netherlands; New Zealand; Singapore; UK; and USA. Different ways governments approach this task are analyzed using webcrawls of the webportals and their neighboring webpages. Variations are considered in relation to the constitutional structures of the countries (i.e. unitary vs federated; centralized vs decentralized).This research highlights information referral versus information repository webportal designs, the latter of which appears to arise more in unitary and city states, than federal states. The hyperlink networks also demonstrate the important structural role of commercial social media websites in half of the countries, revealing a new interactive webportal design. Despite being constructed as whole-of-government entryways, national government webportals typically fail to connect to regional and local tiers of government. The paper provides the basis for assessing the effectiveness of different portal designs and investigating how portal designs arise out of varied government institutional settings. 相似文献
138.
Investigating the factors influencing teachers’ use of ICT in teaching in Bruneian secondary schools
The primary focus of the research study described in this paper was to assess the status quo of teachers’ use of Information and Communication Technology in teaching in terms of the factors that influence their use. Using a survey questionnaire, data was collected from a total of 1,891 secondary school teachers in all government schools in Negara Brunei Darussalam. Structural equation modelling, using AMOS 5.0 software, was employed as the major statistical analytic technique for a series of data analyses and assessment of the Theory of Planned Behaviour, the theoretical model that underpinned the study. Findings presented in this paper indicate that Bruneian teachers’ use of ICT in teaching was influenced by their personal (attitude), social (subjective norms), and control (perceived behavioural control) factors. 相似文献
139.
Deepak Kumar Pasupula P. S. Reddy 《Indian journal of clinical biochemistry : IJCB》2014,29(4):479-484
To determine the normal range of Hemoglobin and cutoff values in healthy adults of Southern India, blood samples were analyzed for parameters of RBC and iron metabolism in 177 male and 203 female medical students. The data were compared with the American white population (NHANES III) and the WHO criteria for detection of anemia. The mean values for hemoglobin and hematocrit in male students differed minimally from American white males. However, values for parameters of iron metabolism were lower except total iron binding capacity (TIBC) which was higher. In female students, hemoglobin, hematocrit and parameters of iron metabolism were lower than American white females, except TIBC which was higher. Lower 5th percentile cutoff point (Mean − 1.645 SD) in males and females were 13.5 and 10 g/dl respectively. In conclusion, South Indian adult males have Hb values similar to American male adults, but South Indian females have considerably lower Hb levels than American females, raising the questions about appropriateness of WHO or US criteria for detection of anemia in Indian females. 相似文献
140.
The present study was carried out to investigate the protective role of Triphala (a combination in equal proportions by weight
of fruit powder of Terminalia belerica, Terminalia chebula and Emblica officinalis) against 1,2-dimethylhydrazinedihydrochloride (DMH) induced Endoplasmic reticulum stress (ER stress) in mouse liver. An oral
dose of 3 mg/kg body wt in drinking water for 5 weeks significantly (P < 0.001) increased the levels of serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase
(SGPT), serum Alkaline phosphatase (ALP) and total bilirubin thus suggesting damage to mouse liver and biliary dysfunction.
The DMH administration invariably led to increase in the liver microsomal proteins of molecular weight of about 29 (ERp29)
and 53 kDa (ERp53) and decrease in the protein of molecular weight of 36 kDa (ERp36) thereby suggesting the interference of
DMH and its metabolites with normal protein biosynthesis and folding, in the reticular membranes of the liver cells thus developing
ER stress. Histological studies show necrosis, large sized hepatocytes with increased N:C ratio, aberrant mitotic figures
and prominent nucleoli in the liver of DMH treated mice. In animals fed 5% Triphala in diet (w/w) during DMH administration,
there was significant decrease in the above changes in the liver suggesting the suppression of DMH induced ER stress in liver.
Triphala significantly (P < 0.05) decreased lipid peroxidation and also the activity of lactate dehydrogenase (LDH) in mouse liver. It simultaneously
increased the level of reduced glutathione (GSH) and the activity of glutathione-S-transferase (GST) thereby suggesting that
it prevents peroxidative damage and also diverts the active metabolites (electrophiles) of DMH from their interactions with
critical cellular bio-molecules which could be responsible for its protective action against DMH. 相似文献