全文获取类型
收费全文 | 28163篇 |
免费 | 340篇 |
国内免费 | 72篇 |
专业分类
教育 | 20220篇 |
科学研究 | 2579篇 |
各国文化 | 258篇 |
体育 | 2137篇 |
综合类 | 50篇 |
文化理论 | 263篇 |
信息传播 | 3068篇 |
出版年
2021年 | 245篇 |
2020年 | 340篇 |
2019年 | 512篇 |
2018年 | 1310篇 |
2017年 | 1351篇 |
2016年 | 1075篇 |
2015年 | 499篇 |
2014年 | 643篇 |
2013年 | 4867篇 |
2012年 | 688篇 |
2011年 | 912篇 |
2010年 | 828篇 |
2009年 | 661篇 |
2008年 | 748篇 |
2007年 | 855篇 |
2006年 | 556篇 |
2005年 | 567篇 |
2004年 | 506篇 |
2003年 | 472篇 |
2002年 | 375篇 |
2001年 | 498篇 |
2000年 | 433篇 |
1999年 | 388篇 |
1998年 | 218篇 |
1997年 | 227篇 |
1996年 | 272篇 |
1995年 | 210篇 |
1994年 | 236篇 |
1993年 | 217篇 |
1992年 | 338篇 |
1991年 | 340篇 |
1990年 | 351篇 |
1989年 | 336篇 |
1988年 | 270篇 |
1987年 | 287篇 |
1986年 | 304篇 |
1985年 | 298篇 |
1984年 | 271篇 |
1983年 | 290篇 |
1982年 | 237篇 |
1981年 | 228篇 |
1980年 | 216篇 |
1979年 | 340篇 |
1978年 | 266篇 |
1977年 | 212篇 |
1976年 | 219篇 |
1975年 | 182篇 |
1974年 | 184篇 |
1973年 | 159篇 |
1971年 | 180篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
151.
Facebook is challenging professional journalism. These challenges were evident in three incidents from 2016: the allegation that Facebook privileged progressive-leaning news on its trending feature; Facebook’s removal of the Pulitzer Prize-winning “Napalm Girl” photo from the pages of prominent users; and the proliferation of “fake news” during the US presidential election. Using theoretical concepts from the field of boundary work, this paper examines how The Guardian, The New York Times, Columbia Journalism Review and Poynter editorialized Facebook’s role in these three incidents to discursively construct the boundary between the value of professional journalism to democracy and Facebook’s ascendant role in facilitating essential democratic functions. Findings reveal that these publications attempted to define Facebook as a news organization (i.e., include it within the boundaries of journalism) so that they could then criticize the company for not following duties traditionally incumbent upon news organizations (i.e., place it outside the boundaries of journalism). This paper advances scholarship that focuses on both inward and outward conceptions of boundary work, further explores the complex challenge of defining who a journalist is in the face of rapidly changing technological norms, and advances scholarship in the field of media ethics that positions ethical analysis at the institutional level. 相似文献
152.
153.
154.
155.
156.
157.
158.
V. V. Arutyunov 《Scientific and Technical Information Processing》2017,44(1):64-68
This article considers the dynamics and specifics of training highly qualified scientific staff (philosophy doctors and doctors of sciences) in the field of information security and data protection in a 10-year period of 2004–2013 in basic research specialties as classified by the Higher Attestation Commission (VAC) of the Ministry of Education and Science of the Russian Federation. 相似文献
159.
B. G. C. Maisonneuve T. Honegger J. Cordeiro O. Lecarme T. Thiry D. Fuard K. Berton E. Picard M. Zelsmann D. Peyrade 《Biomicrofluidics》2016,10(2)
With the rise of microfluidics for the past decade, there has come an ever more pressing need for a low-cost and rapid prototyping technology, especially for research and education purposes. In this article, we report a rapid prototyping process of chromed masks for various microfluidic applications. The process takes place out of a clean room, uses a commercially available video-projector, and can be completed in less than half an hour. We quantify the ranges of fields of view and of resolutions accessible through this video-projection system and report the fabrication of critical microfluidic components (junctions, straight channels, and curved channels). To exemplify the process, three common devices are produced using this method: a droplet generation device, a gradient generation device, and a neuro-engineering oriented device. The neuro-engineering oriented device is a compartmentalized microfluidic chip, and therefore, required the production and the precise alignment of two different masks. 相似文献
160.