全文获取类型
收费全文 | 83101篇 |
免费 | 7261篇 |
国内免费 | 3876篇 |
学科分类
工业技术 | 94238篇 |
出版年
2024年 | 161篇 |
2023年 | 1348篇 |
2022年 | 2171篇 |
2021年 | 3253篇 |
2020年 | 2611篇 |
2019年 | 2249篇 |
2018年 | 2490篇 |
2017年 | 2870篇 |
2016年 | 2557篇 |
2015年 | 3401篇 |
2014年 | 4432篇 |
2013年 | 5143篇 |
2012年 | 5747篇 |
2011年 | 6111篇 |
2010年 | 5365篇 |
2009年 | 5067篇 |
2008年 | 4976篇 |
2007年 | 4699篇 |
2006年 | 4649篇 |
2005年 | 3949篇 |
2004年 | 2645篇 |
2003年 | 2265篇 |
2002年 | 1949篇 |
2001年 | 1865篇 |
2000年 | 1888篇 |
1999年 | 1947篇 |
1998年 | 1482篇 |
1997年 | 1238篇 |
1996年 | 1108篇 |
1995年 | 995篇 |
1994年 | 806篇 |
1993年 | 588篇 |
1992年 | 468篇 |
1991年 | 353篇 |
1990年 | 341篇 |
1989年 | 241篇 |
1988年 | 188篇 |
1987年 | 119篇 |
1986年 | 120篇 |
1985年 | 68篇 |
1984年 | 61篇 |
1983年 | 35篇 |
1982年 | 47篇 |
1981年 | 30篇 |
1980年 | 35篇 |
1979年 | 17篇 |
1978年 | 11篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1974年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Bin Feng Xin Jiang Guisheng Zou Wengan Wang Tianming Sun Heng Yang Guanlei Zhao Mingye Dong Yu Xiao Hongwei Zhu Lei Liu 《Advanced functional materials》2021,31(29):2102359
The realization of liquid metal-based wearable systems will be a milestone toward high-performance, integrated electronic skin. However, despite the revolutionary progress achieved in many other components of electronic skin, liquid metal-based flexible sensors still suffer from poor sensitivity due to the insufficient resistance change of liquid metal to deformation. Herein, a nacre-inspired architecture composed of a biphasic pattern (liquid metal with Cr/Cu underlayer) as “bricks” and strain-sensitive Ag film as “mortar” is developed, which breaks the long-standing sensitivity bottleneck of liquid metal-based electronic skin. With 2 orders of magnitude of sensitivity amplification while maintaining wide (>85%) working range, for the first time, liquid metal-based strain sensors rival the state-of-art counterparts. This liquid metal composite features spatially regulated cracking behavior. On the one hand, hard Cr cells locally modulate the strain distribution, which avoids premature cut-through cracks and prolongs the defect propagation in the adjacent Ag film. On the other hand, the separated liquid metal cells prevent unfavorable continuous liquid-metal paths and create crack-free regions during strain. Demonstrated in diverse scenarios, the proposed design concept may spark more applications of ultrasensitive liquid metal-based electronic skins, and reveals a pathway for sensor development via crack engineering. 相似文献
13.
14.
15.
16.
Dan Ye Kaiyu Wang Haijiao Yang Xingang Zhao 《International Journal of Adaptive Control and Signal Processing》2020,34(11):1677-1696
In this article, an adaptive fuzzy output feedback control method is presented for nonlinear time-delay systems with time-varying full state constraints and input saturation. To overcome the problem of time-varying constraints, the integral barrier Lyapunov functions (IBLFs) integrating with dynamic surface control (DSC) are applied for the first time to keep the state from violating constraints. The effects of unknown time delays can be removed by using designed Lyapunov-Krasovskii functions (LKFs). An auxiliary design system is introduced to solve the problem of input saturation. The unknown nonlinear functions are approximated by the fuzzy logic systems (FLS), and the unmeasured states are estimated by a designed fuzzy observer. The novel controller can guarantee that all signals remain semiglobally uniformly ultimately bounded and satisfactory tracking performance is achieved. Finally, two simulation examples illustrate the effectiveness of the presented control methods. 相似文献
17.
18.
19.
20.