全文获取类型
收费全文 | 220篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
教育 | 106篇 |
科学研究 | 82篇 |
各国文化 | 3篇 |
体育 | 11篇 |
文化理论 | 2篇 |
信息传播 | 24篇 |
出版年
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 10篇 |
2020年 | 10篇 |
2019年 | 9篇 |
2018年 | 26篇 |
2017年 | 16篇 |
2016年 | 10篇 |
2015年 | 16篇 |
2014年 | 16篇 |
2013年 | 19篇 |
2012年 | 12篇 |
2011年 | 10篇 |
2010年 | 7篇 |
2009年 | 16篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2001年 | 1篇 |
1998年 | 3篇 |
1994年 | 1篇 |
1988年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有228条查询结果,搜索用时 9 毫秒
61.
Aaron S. Veenstra Mohammad Delwar Hossain Benjamin A. Lyons 《Mass Communication and Society》2014,17(6):874-897
This study examines the roles of partisanship, partisan media use, and political discussion in the development of belief gaps. Using national survey data, we construct models of political identity, media use, and discussion factors predicting beliefs on five contested political issues and find that ideology and partisanship are generally stronger predictors of beliefs than is education. Notably, each has independent effects on belief outcomes. Contrary to some concerns that the Internet especially promotes partisan clustering, use of partisan traditional media—television and radio—is by far the strongest information-related predictor of belief outcomes, whereas partisan social media use and partisan discussion are relatively weak and inconsistent. These findings suggest that political elites continue to exert significant influence over the perceptions of rank and file partisans. 相似文献
62.
Mojtaba Salehi Isa Nakhai Kamalabadi Mohammad Bagher Ghaznavi Ghoushchi 《Education and Information Technologies》2014,19(4):713-735
Material recommender system is a significant part of e-learning systems for personalization and recommendation of appropriate materials to learners. However, in the existing recommendation algorithms, dynamic interests and multi-preference of learners and multidimensional-attribute of materials are not fully considered simultaneously. Moreover, these algorithms cannot effectively use the learner’s historical sequential patterns of material accessing in recommendation. For addressing these problems and improving the accuracy and quality of recommendation, a new material recommender system framework based on sequential pattern mining and multidimensional attribute-based collaborative filtering (CF) is proposed. In the sequential pattern based approach, modified Apriori and PrefixSpan algorithms are implemented to discover latent patterns in accessing of materials and use them for recommendation. Leaner Preference Tree (LPT) is introduced to take into account multidimensional-attribute of materials, and learners’ rating and model dynamic and multi-preference of learners in the multidimensional attribute-based CF approach. Finally, the recommendation results of two approaches are combined using cascade, weighted and mixed methods. The proposed method outperforms the previous algorithms on the classification accuracy measures and the learner’s real learning preference can be satisfied accurately according to the real-time up dated contextual information. 相似文献
63.
The global knowledge economy has turned higher education into a key player in societal development. Internationalization benefits higher education institutions in several aspects, such as improvement and visibility in international rankings, revenue generation via tuition fees and external funding, improvement of research and teaching quality, integration with academic communities and familiarization with scholarly attitudes. In this study, we provide insights into the challenges of internationalization faced by higher education institutions in Iran as a developing country. Several policies and practices have been adopted in Iran to improve internationalization efforts; however, these activities have had little impact on the quality of research and educational programs at Iran's universities. Understanding the challenges they face in a systematic way can help identify different factors and develop a set of suggestions to increase the quality and quantity of international cooperation. We formulate our suggestions based on the opportunities provided by the digitalization solutions in the aftermath of the COVID-19 pandemic and the increasing importance of the UN's Sustainable Development Goals in both global and national environments. We interviewed 15 faculty members in Iranian higher education institutions and 14 managers in charge of international affairs at universities in Iran. In addition, data extracted from three forums on Iranian higher education internationalization are analysed. Using a grounded theory approach, we group the challenges into macro-, institutional and individual levels and then suggest a number of practices and policies to increase the quantity and quality of internationalization efforts. 相似文献
64.
Maryam Farahnak Zarabi Ali Farhangi Samaneh Khademi Mazdeh Zahra Ansarian Davod Zare Mohammad Reza Mehrabi Azim Akbarzadeh 《Indian journal of clinical biochemistry : IJCB》2014,29(2):154-160
Carboxylate-modified gold nanoparticles (GNPs) were synthesized in a simple one-step process based on the reduction of tetrachloroauric acid by aspartic acid in water. GNPs were identified by UV–Vis spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy. Conjugation of protein molecules with functionalized nanoparticles was performed through electrostatic interaction. The GNP–protein conjugates were characterized by gel electrophoresis. The interaction between functionalized GNPs and protein molecules lead to conformational transition of protein structure after conjugation of protein with GNPs. This process was investigated by fluorescence spectroscopy and circular dichroism spectroscopy. 相似文献
65.
Ali Farhangi Dariush Norouzian Mohammad Reza Mehrabi Mohsen Chiani Zahra Saffari Maryam Farahnak Azim Akbarzadeh 《Indian journal of clinical biochemistry : IJCB》2014,29(4):406-417
The objective of this study is to induce experimental diabetes mellitus by streptozotocin in normal adult Wistar rats via comparison of changes in body weight, consumption of food, volume of water, urine and levels of glucose, insulin and C-peptide in serum, between normal and diabetic rats. Intra-venous injection of 60 mg/kg dose of streptozotocin in 250–300 g (75–90 days) adult Wistar rats makes pancreas swell and causes degeneration in Langerhans islet β-cells and induces experimental diabetes mellitus in 2–4 days. For a microscopic study of degeneration of Langerhans islet β-cells of diabetic rats, biopsy from pancreas tissue of diabetic and normal rats, staining and comparison between them, were done. In this process, after collagenase digestion of pancreas, islets were isolated, dissociated and identified by dithizone method and then with enzymatic procedure by DNase and trypsin, the islet cells changed into single cells and β-cells were identified by immune fluorescence method and then assayed by flow-cytometer. Donor tissue in each step of work was prepared from 38 adult male Wistar rats weighted 250–300 g (75–90 days). Transplantation was performed in rats after 2–4 weeks of diabetes induction. In this study, the levels of insulin, C-peptide and glucose in diabetic rats reached to normal range as compared to un-diabetic rats in 20 days after transplantation of islet cells. Transplantation was performed under the cortex of testis as immunoisolated place for islet cells transplantation. 相似文献
66.
67.
Mohammad Delwar Hossain Aaron S. Veenstra 《Journal of Intercultural Communication Research》2017,46(5):478-496
This study examines the uses and gratifications of language in social media among the Indian subcontinental diaspora in the United States, based on data collected from an online survey of 535 adult immigrants following a snowballing technique. Results showed the use of native language is related to the use of home country media, while the use of English language is related to emotional adjustment. This study contributes to the literature on social media, community, and language preference by opening avenues for conducting further research on the usage of language in social media among the Indian subcontinental diaspora in the United States. The findings of this study contribute to an understanding of the influence of social media on language preference. 相似文献
68.
Mohammad Sadegh Cheri Hamidreza Shahraki Jalal Sadeghi Mohammadreza Salehi Moghaddam Hamid Latifi 《Biomicrofluidics》2014,8(5)
Measurement and control of pressure-driven flow (PDF) has a great potential to enhance the performance of chemical and biological experiments in Lab on a Chip technology. In this paper, we present an optofluidic flow sensor for real-time measurement and control of PDF. The optofluidic flow sensor consists of an on-chip micro Venturi and two optical Fabry-Pérot (FP) interferometers. Flow rate was measured from the fringe shift of FP interferometers resulted from movement fluid in the on-chip micro Venturi. The experimental results show that the optofluidic flow sensor has a minimum detectable flow change of 5 nl/min that is suitable for real time monitoring and control of fluids in many chemical and biological experiments. A Finite Element Method is used to solve the three dimensional (3D) Navier–Stokes and continuity equations to validate the experimental results. 相似文献
69.
In this paper, a method is proposed to reject disturbances in the model predictive control (MPC) strategy. In addition, uncertainties in the system parameters (i.e., internal disturbances) are considered as well. To achieve these goals, adaptive neural networks are designed as the predictor model and as the nonlinear disturbance observer, respectively. The disturbances are rejected via the optimization problem of the MPC. Stability of the closed-loop system is studied based on the Input-to-State Stability method. The proposed method is applied to the pH neutralization process and CSTR system and its effectiveness in optimal rejection of the disturbances and satisfying the system constrains is compared with the feed-forward control method. 相似文献
70.
Research in natural language processing has increasingly focused on normalizing Twitter messages. Currently, while different well-defined approaches have been proposed for the English language, the problem remains far from being solved for other languages, such as Malay. Thus, in this paper, we propose an approach to normalize the Malay Twitter messages based on corpus-driven analysis. An architecture for Malay Tweet normalization is presented, which comprises seven main modules: (1) enhanced tokenization, (2) In-Vocabulary (IV) detection, (3) specialized dictionary query, (4) repeated letter elimination, (5) abbreviation adjusting, (6) English word translation, and (7) de-tokenization. A parallel Tweet dataset, consisting of 9000 Malay Tweets, is used in the development and testing stages. To measure the performance of the system, an evaluation is carried out. The result is promising whereby we score 0.83 in BLEU against the baseline BLEU, which scores 0.46. To compare the accuracy of the architecture with other statistical approaches, an SMT-like normalization system is implemented, trained, and evaluated with an identical parallel dataset. The experimental results demonstrate that we achieve higher accuracy by the normalization system, which is designed based on the features of Malay Tweets, compared to the SMT-like system. 相似文献