全文获取类型
收费全文 | 20427篇 |
免费 | 357篇 |
国内免费 | 55篇 |
专业分类
教育 | 14993篇 |
科学研究 | 1367篇 |
各国文化 | 256篇 |
体育 | 1730篇 |
综合类 | 45篇 |
文化理论 | 153篇 |
信息传播 | 2295篇 |
出版年
2022年 | 144篇 |
2021年 | 244篇 |
2020年 | 368篇 |
2019年 | 566篇 |
2018年 | 781篇 |
2017年 | 775篇 |
2016年 | 760篇 |
2015年 | 504篇 |
2014年 | 613篇 |
2013年 | 4182篇 |
2012年 | 586篇 |
2011年 | 572篇 |
2010年 | 494篇 |
2009年 | 478篇 |
2008年 | 505篇 |
2007年 | 468篇 |
2006年 | 485篇 |
2005年 | 411篇 |
2004年 | 293篇 |
2003年 | 308篇 |
2002年 | 252篇 |
2001年 | 397篇 |
2000年 | 314篇 |
1999年 | 272篇 |
1998年 | 182篇 |
1997年 | 178篇 |
1996年 | 190篇 |
1995年 | 172篇 |
1994年 | 180篇 |
1993年 | 156篇 |
1992年 | 230篇 |
1991年 | 227篇 |
1990年 | 255篇 |
1989年 | 229篇 |
1988年 | 188篇 |
1987年 | 191篇 |
1986年 | 198篇 |
1985年 | 189篇 |
1984年 | 195篇 |
1983年 | 175篇 |
1982年 | 143篇 |
1981年 | 154篇 |
1980年 | 136篇 |
1979年 | 203篇 |
1978年 | 178篇 |
1977年 | 124篇 |
1976年 | 128篇 |
1975年 | 115篇 |
1974年 | 114篇 |
1971年 | 120篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
91.
Jayson L. Dibble 《Communication Research Reports》2018,35(2):112-120
Is the reluctance to share bad news (i.e., the MUM effect) motivated more by a public display or private concern, and does it benefit mainly the messenger or the recipient? An experiment (N = 309) that crossed good/bad news with three communication channels (face-to-face, text messaging, e-mail) revealed that messenger reluctance was greatest under conditions of bad news and did not vary based on the channel through which the recipient contacted the messenger. In contrast with earlier work, this MUM effect was more consistent with a private fear of distressing the recipient. Theoretical implications and limitations are discussed. 相似文献
92.
Debasis?GangulyEmail authorView authors OrcID profile Gareth?J.?F.?Jones Aarón?Ramírez-de-la-Cruz Gabriela?Ramírez-de-la-Rosa Esaú?Villatoro-Tello 《Information Retrieval》2018,21(1):1-23
Automatic detection of source code plagiarism is an important research field for both the commercial software industry and within the research community. Existing methods of plagiarism detection primarily involve exhaustive pairwise document comparison, which does not scale well for large software collections. To achieve scalability, we approach the problem from an information retrieval (IR) perspective. We retrieve a ranked list of candidate documents in response to a pseudo-query representation constructed from each source code document in the collection. The challenge in source code document retrieval is that the standard bag-of-words (BoW) representation model for such documents is likely to result in many false positives being retrieved, because of the use of identical programming language specific constructs and keywords. To address this problem, we make use of an abstract syntax tree (AST) representation of the source code documents. While the IR approach is efficient, it is essentially unsupervised in nature. To further improve its effectiveness, we apply a supervised classifier (pre-trained with features extracted from sample plagiarized source code pairs) on the top ranked retrieved documents. We report experiments on the SOCO-2014 dataset comprising 12K Java source files with almost 1M lines of code. Our experiments confirm that the AST based approach produces significantly better retrieval effectiveness than a standard BoW representation, i.e., the AST based approach is able to identify a higher number of plagiarized source code documents at top ranks in response to a query source code document. The supervised classifier, trained on features extracted from sample plagiarized source code pairs, is shown to effectively filter and thus further improve the ranked list of retrieved candidate plagiarized documents. 相似文献
93.
Textbook vetting and evaluation process intends to ensure that the materials provided are relevant, of the required quality, suitable ad would enhance learning efficiency and effectiveness. The paper investigates the role of publishers and Tanzania Institute of Education (TIE) in the textbooks vetting and evaluation process; examines factors used to vet, evaluate and approve primary and secondary school textbooks in Tanzania and proposes Strategies that would enhance the textbook vetting, evaluation and process. The study used a mixed method research design. Respondents were selected educational publishers; MoEVT, Baraza la Kiswahili Tanzania, TIE, and Publishers Association of Tanzania. Questionnaire and semi- structured interview were used to collect data which were analysed qualitatively and quantitatively. Major findings of the study were; textbooks vetting and evaluation process is not professionally conducted although standard criteria have been established; there is not well established roles among key players involved in the vetting and evaluation process leading to conflict of interest between TIE and the publishers. The study recommends establishing an independent professional evaluation board and a well-defined timetable and effective communication among various players; enacting a book policy and adopting a limited multiple-textbook publishing system. 相似文献
94.
95.
Against the backdrop of Spain’s Transparency Act, this article discusses the presence or otherwise of a series of document types, proposed as management-related transparency indicators, on 61 (8 national and 53 provincial) historic archive websites. Although examples of good practice were identified, the information provided was found to be scant, in particular as regards lines of action, organisational objectives and yearly reports. The information most commonly provided on the websites included the collection classification chart, service use regulations and citizen charters. The inference drawn was that archives, so intently focused on their role in the application of the Act by the organisations they serve, neglect their own administrative obligations in respect of its provisions. The recommendation is that as government-funded and subsidised public service institutions, historic archives should exercise transparency by furnishing the information stipulated in the Act on their websites. 相似文献
96.
Daniel Maier A. Waldherr P. Miltner G. Wiedemann A. Niekler A. Keinert 《Communication methods and measures》2018,12(2-3):93-118
ABSTRACTLatent Dirichlet allocation (LDA) topic models are increasingly being used in communication research. Yet, questions regarding reliability and validity of the approach have received little attention thus far. In applying LDA to textual data, researchers need to tackle at least four major challenges that affect these criteria: (a) appropriate pre-processing of the text collection; (b) adequate selection of model parameters, including the number of topics to be generated; (c) evaluation of the model’s reliability; and (d) the process of validly interpreting the resulting topics. We review the research literature dealing with these questions and propose a methodology that approaches these challenges. Our overall goal is to make LDA topic modeling more accessible to communication researchers and to ensure compliance with disciplinary standards. Consequently, we develop a brief hands-on user guide for applying LDA topic modeling. We demonstrate the value of our approach with empirical data from an ongoing research project. 相似文献
97.
98.
99.
100.