全文获取类型
收费全文 | 5240篇 |
免费 | 133篇 |
国内免费 | 131篇 |
专业分类
教育 | 3182篇 |
科学研究 | 944篇 |
各国文化 | 21篇 |
体育 | 336篇 |
综合类 | 347篇 |
文化理论 | 10篇 |
信息传播 | 664篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 72篇 |
2021年 | 155篇 |
2020年 | 130篇 |
2019年 | 102篇 |
2018年 | 69篇 |
2017年 | 90篇 |
2016年 | 61篇 |
2015年 | 212篇 |
2014年 | 360篇 |
2013年 | 406篇 |
2012年 | 434篇 |
2011年 | 488篇 |
2010年 | 447篇 |
2009年 | 365篇 |
2008年 | 348篇 |
2007年 | 373篇 |
2006年 | 275篇 |
2005年 | 216篇 |
2004年 | 132篇 |
2003年 | 180篇 |
2002年 | 185篇 |
2001年 | 141篇 |
2000年 | 95篇 |
1999年 | 54篇 |
1998年 | 27篇 |
1997年 | 21篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1957年 | 2篇 |
排序方式: 共有5504条查询结果,搜索用时 9 毫秒
81.
Cong Liu Feng An Paria S M Gharavi Qinwen Lu Junkun Zha Chao Chen Liming Wang Xiaozhi Zhan Zedong Xu Yuan Zhang Ke Qu Junxiang Yao Yun Ou Zhiming Zhao Xiangli Zhong Dongwen Zhang Nagarajan Valanoor Lang Chen Tao Zhu Deyang Chen Xiaofang Zhai Peng Gao Tingting Jia Shuhong Xie Gaokuo Zhong Jiangyu Li 《国家科学评论(英文版)》2020,7(1):84
Complex oxides with tunable structures have many fascinating properties, though high-quality complex oxide epitaxy with precisely controlled composition is still out of reach. Here we have successfully developed solution-based single-crystalline epitaxy for multiferroic (1-x)BiTi(1-y)/2FeyMg(1-y)/2O3–(x)CaTiO3 (BTFM–CTO) solid solution in large area, confirming its ferroelectricity at the atomic scale with strong spontaneous polarization. Careful compositional tuning leads to a bulk magnetization of 0.07 ± 0.035 μB/Fe at room temperature, enabling magnetically induced polarization switching exhibiting a large magnetoelectric coefficient of 2.7–3.0 × 10−7 s/m. This work demonstrates the great potential of solution processing in large-scale complex oxide epitaxy and establishes novel room-temperature magnetoelectric coupling in epitaxial BTFM–CTO film, making it possible to explore a much wider space of composition, phase, and structure that can be easily scaled up for industrial applications. 相似文献
82.
Hepeng Jia 《国家科学评论(英文版)》2020,7(11):1787
With the fast development of cutting-edge technologies and their greater integration into human life, more ethical challenges emerge. The problem became more salient when the world''s first genetically edited babies were born in China in violation of existing ethical rules. Although the responsible researcher He Jiankui was sentenced for imprisonment for three years last December, it is still necessary to examine the current status of research ethics and the challenges in China. Has China set up a sophisticated research ethics system? For research ethics and their implementation in China, are there unique national characteristics? Can the dominant ethics principles primarily developed from life science research be equally adopted in the emerging artificial intelligence research and development? At an online forum organized by National Science Review (NSR) and through subsequent correspondences among forum participants, NSR Executive Editor-in-Chief Mu-ming Poo and guest moderator Hepeng Jia asked three scientists and three bioethicists or philosophers of science and technology in the field to examine the dynamic development of research ethics in China. Weiwen DuanPhilosopher of Science and Technology at Chinese Academy of Social Sciences, Beijing, China Junjiu HuangLife scientist focused on genetics at Sun Yat-sen University, Guangzhou, China Renzong QiuBioethicist at Chinese Academy of Social Sciences, Beijing, China Qiang SunLife scientist and the principal investigator (PI) of clone monkey program at Shanghai Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China Yi ZengArtificial intelligence scientist at Institute of Automation, Chinese Academy of Sciences, Beijing, China Xiaomei ZhaiBioethicist at Chinese Academy of Medical Sciences/Peking Union Medical College, Beijing, China Mu-ming Poo (Chair)Neurobiologist at Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China Hepeng Jia (Co-chair)Professor of Science Communication at Soochow University, Suzhou, China 相似文献
83.
84.
85.
86.
87.
This study investigated the relationship between Chinese international students’ social networks in the United States and their musical tastes. Based on concept of homophily, this study used a self-reported Social Network Analysis (SNA) survey to examine whether sharing similar musical tastes affected Chinese international students’ relationship, their musical tastes, and music consumption. The results showed that having high musical taste similarity predicted closer relationship between respondents and their alters, and higher likelihood of new music consumption. This study also found that frequent American English-language songs listeners were more likely to have Americans in their social network than less-frequent American English-language songs listeners. 相似文献
88.
针对不同类型事件设计多状态跳转模型,结合两种深度神经网络实现对传统音频事件检测框架的改进。实验表明,在DCASE2017任务2的开发集数据上,改进后的DNN-HMM系统相比于基线系统取得F值8.9%的相对提升和错误率19%的绝对下降;基于多状态跳转模型聚类的卷积神经网络模型(SC-CNN),相比于基线系统取得F值18%的相对提升和错误率30%的绝对下降。 相似文献
89.
科学数据共享FAIR原则:背景、内容及实践 总被引:2,自引:0,他引:2
[目的/意义]FAIR原则已经成为科学数据管理的国际准则,研究该原则的理念内涵将有助于我国科学数据管理工作的布局与实践。[方法/过程]基于文献调研和网络调研,首先从时代特性角度分析了FAIR原则的产生背景;然后透过关键语词详细解析了可发现、可访问、可互操作、可重用4项子原则的具体内容;最后从学术会议、研究成果、科学计划、数据出版四个方面介绍了FAIR原则的研究与实践进展。[结果/结论]文章认为,数据资源持续积累、科学研究范式变革、数据共享全球行动为FAIR原则产生奠定了背景,4项子原则及其15条具体原则层层递进,共同描绘了FAIR体系。未来的科学数据共享系统将朝着融合化、智能化、生态化方向发展。 相似文献
90.
给出了一种用于调整激光高效偏光镜出射光束间距的新型棱镜,利用光斜入射通过平行均匀介质时会发生光束平移的原理,导出了缩·扩束比与棱镜参数的关系以及棱镜的设计公式.选择光以布儒斯特角入射,使得棱镜具有最佳透射比.通过改变棱镜的边长来调整出射光束的剪切差,从而达到光束的缩·扩束的目的. 相似文献