全文获取类型
| 收费全文 | 145篇 |
| 免费 | 3篇 |
| 国内免费 | 2篇 |
专业分类
| 教育 | 83篇 |
| 科学研究 | 28篇 |
| 各国文化 | 2篇 |
| 体育 | 14篇 |
| 综合类 | 2篇 |
| 信息传播 | 21篇 |
出版年
| 2022年 | 10篇 |
| 2021年 | 10篇 |
| 2020年 | 3篇 |
| 2019年 | 12篇 |
| 2018年 | 13篇 |
| 2017年 | 6篇 |
| 2016年 | 1篇 |
| 2015年 | 4篇 |
| 2014年 | 5篇 |
| 2013年 | 19篇 |
| 2012年 | 9篇 |
| 2011年 | 7篇 |
| 2010年 | 6篇 |
| 2009年 | 9篇 |
| 2008年 | 6篇 |
| 2007年 | 5篇 |
| 2006年 | 10篇 |
| 2005年 | 4篇 |
| 2003年 | 2篇 |
| 2001年 | 1篇 |
| 2000年 | 4篇 |
| 1992年 | 2篇 |
| 1985年 | 1篇 |
| 1981年 | 1篇 |
排序方式： 共有150条查询结果，搜索用时 15 毫秒
81.
This paper deals with the problem of delay-dependent stability analysis for neural networks with time-varying delays. First, by constructing an augmented Lyapunov–Krasovskii functional and utilizing a generalized free-weighting matrix integral inequality, an improved stability criterion for the concerned network is derived in terms of linear matrix inequalities. Second, by considering a marginal augmented vector and modifying a Lyapunov–Krasovsii functional, a further enhanced stability criterion is presented. Third, a less conservative stability condition in which a relaxed inequality related to activation functions is added is introduced. Finally, three numerical examples are included to illustrate the advantage and validity of the proposed criteria. 相似文献
82.
This study empirically examines whether the research and development (R&D) activities of foreign-owned firms in Japan differ notably from the R&D activities of domestically-owned firms based on a firm-level panel dataset. Our study carefully disentangles the significant differences in R&D investment behavior of subsidiaries due to three different reasons: having a foreign parent, corporate group affiliation, and the degree of relatedness between business units. The results reveal the following. First, firms that are majority-owned by another firm are less active in R&D than independent firms. Second, foreign ownership does not matter if the parent firm is from a G7 country, but R&D intensity is significantly and positively associated with foreign ownership if the parent firm is from a non-G7 country. Finally, for subsidiaries whose business is related to that of their parent firm, the R&D intensity is lower if the parent is a domestic firm, but higher if it is a foreign firm. These findings imply that globalization and the integration of firms may not only affect production patterns and global supply chains, but may also have an important impact on the level of domestic R&D activities. 相似文献
83.
Fabrication methods for the development of multiplexed immunoassay platforms primarily depend on the individual functionalization of reaction chambers to achieve a heterogeneous reacting substrate composition, which increases the overall manufacturing time and cost. Here, we describe a new type of low-cost fabrication method for a scalable immunoassay platform based on cotton threads. The manufacturing process involves the fabrication of functionalized fibers and the arrangement of these fibers into a bundle; this bundle is then sectioned to make microarray-like particles with a predefined surface architecture. With these sections, composed of heterogeneous thread fragments with different types of antibodies, we demonstrated quantitative and 7-plex immunoassays. We expect that this methodology will prove to be a versatile, low-cost, and highly scalable method for the fabrication of multiplexed bioassay platforms. 相似文献
84.
85.
Kwon Kyungbin Ottenbreit-Leftwich Anne T. Brush Thomas A. Jeon Minji Yan Ge 《Educational technology research and development : ETR & D》2021,69(5):2761-2787
Educational technology research and development - This study investigated how a computer science (CS) problem-based curriculum impacted elementary students’ CS learning and attitudes. Four... 相似文献
86.
Rahman Tazizur Kim Yang Sok Noh Mijin Lee Choong Kwon 《Educational technology research and development : ETR & D》2021,69(2):1325-1351
Educational technology research and development - Social-Media-Based Learning (SMBL) is the use of social-media-based platforms, such as Twitter, Google Plus, Facebook, and YouTube, for learning... 相似文献
87.
88.
An optofluidic maskless photopolymerization process was developed for in situ negatively charged nanoporous hydrogel [poly-AMPS (2-acrylamido-2-methyl-1-propanesulfonic acid)] fabrication. The optofluidic maskless lithography system, which combines a high power UV source and digital mirror device, enables fast polymerization of arbitrary shaped hydrogels in a microfluidic device. The poly-AMPS hydrogel structures were positioned near the intersections of two microchannels, and were used as a cation-selective filter for biological sample preconcentration. Preconcentration dynamics as well as the fabricated polymer shape were analyzed in three-dimensions using fluorescein sample and a confocal microscope. Finally, single-stranded DNA preconcentration was demonstrated for polymerase chain reaction-free signal enhancement. 相似文献
89.
90.
"数字化微型气象站"在科学教育中的应用与思考 总被引：2，自引：0，他引：2
"数字化微型气象站"是一种基于手持技术(Handheld technology)的先进的便携式气象数据采集系统.本文首先介绍了数字化微型气象站的组成与特点,重点探讨了它在科学教育中应用的四个层面,即通过运用"数字化微型气象站"进行科学教育,增长学生的科学知识,提高学生的科学探究能力,增强学生的科学观以及培养学生的科学品质,并简述了"数字化微型气象站"在我国的应用状况,最后提出了它在科学教育中应用与推广的相关思考. 相似文献