全文获取类型
收费全文 | 277篇 |
免费 | 6篇 |
专业分类
教育 | 170篇 |
科学研究 | 66篇 |
各国文化 | 4篇 |
体育 | 7篇 |
文化理论 | 4篇 |
信息传播 | 32篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 23篇 |
2018年 | 27篇 |
2017年 | 19篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 15篇 |
2013年 | 43篇 |
2012年 | 11篇 |
2011年 | 16篇 |
2010年 | 10篇 |
2009年 | 8篇 |
2008年 | 1篇 |
2007年 | 10篇 |
2006年 | 6篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1975年 | 1篇 |
排序方式: 共有283条查询结果,搜索用时 515 毫秒
41.
Katja Derr Reinhold Hübl Mohammed Zaki Ahmed 《European Journal of Engineering Education》2018,43(6):911-926
The article describes the development and evaluation of a web-based pre-course in mathematics, delivered to four cohorts of engineering students at a German university. Based on demographic, personal, and learning-related data relationships between students’ preconditions, their learning gains in the pre-course, and study success in the degree programme were analysed. The results support the existing literature in that domain-related prior knowledge and secondary school achievement play a dominant role regarding study success in engineering. The analyses also showed that the influence of cognitive predictors could only be compensated for by a strong learner engagement. At-risk students with high pre-course learning gains showed significantly better first-year performance. The number of self-tests a student attempted was positively related to pre-course learning gains and even to first-year performance, suggesting that this variable is a good indicator of student engagement. 相似文献
42.
Shaymaa M. M. Yahya Shadia A. Fathy Zakaria A. El-Khayat Safinaz E. El-Toukhy Ahmed R. Hamed Marwa G. A. Hegazy Heba K. Nabih 《Indian journal of clinical biochemistry : IJCB》2018,33(1):21-30
Hepatocellular carcinoma (HCC) is a hypervascular primary liver cancer characterized by rapid progression, besides, resistance to traditional chemotherapeutic agents. It has been shown that microRNAs play critical roles in regulation of tumor cell sensitivity to drugs through modulating the expression of genes involved in drug transport. The present study investigated whether restoration of miR-122 in HCC cells could alter the cell cycle distribution and the expression of multidrug resistance (MDR)-related genes (ABCB1, ABCC1, ABCG2 and ABCF2). After overexpression of miR-122 in HepG2 cells treated or untreated with doxorubicin doses, total RNAs and protein extracts were isolated for application of QRT-PCR and western blotting techniques. Moreover, cell cycle distribution was monitored by flow cytometry. Our results revealed that, the over expression of miR-122 in HepG2 cells treated or untreated with doxorubicin could modulate the sensitivity of cells to chemotherapeutic drug through downregulation of MDR-related genes, ABCB1 and ABCF2. Interpretation of cell cycle distribution revealed that, the anti-proliferative effect of miR-122 is associated with the accumulation of cells in G0/G1 phase. Moreover, treatment with miR-122 and doxorubicin resulted in high percentage of HCC cells in G0/G1 phase. Taken together, our findings revealed that, overexpression of miR-122 inhibited HCC cell growth by inducing cell cycle arrest and this arrest is associated with down-regulation of MDR-related genes. 相似文献
43.
44.
Nabeel Al-Qirim Ali Tarhini Kamel Rouibah Serhani Mohamd Aishah Rashid Yammahi Maraim Ahmed Yammahi 《Education and Information Technologies》2018,23(1):129-142
This research examines the learning preferences of students in UAE University (UAEU). The uniqueness of this research emanates from the fact that no prior research examined this area from the UAE’s perspective. Thus, this research embarks on the fact that student learning strategies vary from one country to another due to many factors. This research utilizes six learning strategies extended from the literature and attempts to examine their importance on UAEU students using survey research. The selected learning strategies were students” motivation, time-poorness, mastery effort, assessment focus, competitiveness, and listening. This research provided interesting insights and contrasts pertaining to the learning strategies of UAEU students. Implications are discussed highlighting different theoretical as well as professional contributions and contentions and portrayed a path where pending issues could be addressed by future research. 相似文献
45.
Walid E. Zahran Kholoud A. Salah El-Dien Philip G. Kamel Ahmed Shawky El-Sawaby 《Indian journal of clinical biochemistry : IJCB》2013,28(2):141-146
Tumor necrosis factor (TNF-α) is a cytokine involved in systemic inflammation during acute phase reactions. The current study was designed to investigate the levels of pro-inflammatory cytokine (TNF-α) along with the anti-inflammatory cytokine (IL-10) during progression of non-alcoholic fatty liver disease (NAFLD) from simple steatosis to non-alcoholic steatohepatitis (NASH) and fibrosis in diabetic patients, and correlate the levels of cytokines with the progression of NAFLD. Fifty-two diabetic patients compared to 18 healthy controls were participated in this study. Based on clinical diagnosis, patients were divided into three groups: simple steatosis, NASH and fibrosis. Serum liver function tests, fasting blood glucose, bilirubin, ALT, AST, TNF-α, IL-10 and lipid profile were measured. TNF-α levels were significantly higher in NAFLD patients compared to control subjects with a significant positive correlation with body mass index and fasting blood glucose (FBG) but with negative correlation with IL-10. Serum IL-10 levels were significantly lower in NAFLD patients compared with controls. A positive correlation between IL-10 and HDL-C with concomitant negative correlation between IL-10 and FBG and triacylglycerides was found. Cytokine analyses showed that there was a prominent imbalance between TNF-α and IL-10 in patients with NAFLD, and this imbalance increase by increasing the progression of NAFLD especially in obese diabetic patients. TNF-α and IL-10 could be used in diagnosis and follow-up of NAFLD stages in a way to avoid liver biopsies in greater proportion of patients. 相似文献
46.
47.
Sohaib Ahmed Sameena Javaid Moazzam Fareed Niazi Anzar Alam Adnan Ahmad Murad Ali Baig 《Technology, Pedagogy and Education》2019,28(1):53-71
The use of Bluetooth Low Energy (BLE) beacons is becoming widespread for context-aware learning environments. This technology can be used in indoor and outdoor settings such as museums, shops, home and schools in order to identify the location of learners and their contexts. Specifically, in the constructivist view of learning, learners can use such sensing technology for constructing knowledge and experiencing learning at any time, anywhere. However, exploration of such technology has been limited in the constructivist context-aware ubiquitous learning (U-learning) literature. For this purpose, the authors evaluated two android-based U-learning applications: one was an outdoor learning environment in a garden, the other was about locating books in a library. The applications were implemented and tested with school and university students. The qualitative results are presented in this article, and show how such sensing technology is promising for both pedagogical environments. 相似文献
48.
49.
50.
Ines Ben Chobba Amine Elleuch Imen Ayadi Lamia Khannous Ahmed Namsi Frederique Cerqueira Noureddine Drira Néji Gharsallah Tatiana Vallaeys 《Journal of Zhejiang University. Science. B》2013,14(12):1084-1099
Endophytic flora plays a vital role in the colonization and survival of host plants, especially in harsh environments, such as arid regions. This flora may, however, contain pathogenic species responsible for various troublesome host diseases. The present study is aimed at investigating the diversity of both cultivable and non-cultivable endophytic fungal floras in the internal tissues (roots and leaves) of Tunisian date palm trees (Phoenix dactylifera). Accordingly, 13 isolates from both root and leaf samples, exhibiting distinct colony morphology, were selected from potato dextrose agar (PDA) medium and identified by a sequence match search wherein their 18S–28S internal transcribed spacer (ITS) sequences were compared to those available in public databases. These findings revealed that the cultivable root and leaf isolates fell into two groups, namely Nectriaceae and Pleosporaceae. Additionally, total DNA from palm roots and leaves was further extracted and ITS fragments were amplified. Restriction fragment length polymorphism (RFLP) analysis of the ITS from 200 fungal clones (leaves: 100; roots: 100) using HaeIII restriction enzyme revealed 13 distinct patterns that were further sequenced and led to the identification of Alternaria, Cladosporium, Davidiella (Cladosporium teleomorph), Pythium, Curvularia, and uncharacterized fungal endophytes. Both approaches confirmed that while the roots were predominantly colonized by Fusaria (members of the Nectriaceae family), the leaves were essentially colonized by Alternaria (members of the Pleosporaceae family). Overall, the findings of the present study constitute, to the authors’ knowledge, the first extensive report on the diversity of endophytic fungal flora associated with date palm trees (P. dactylifera). 相似文献