全文获取类型
收费全文 | 5487篇 |
免费 | 634篇 |
国内免费 | 471篇 |
专业分类
电工技术 | 745篇 |
综合类 | 467篇 |
化学工业 | 193篇 |
金属工艺 | 64篇 |
机械仪表 | 341篇 |
建筑科学 | 122篇 |
矿业工程 | 74篇 |
能源动力 | 81篇 |
轻工业 | 55篇 |
水利工程 | 50篇 |
石油天然气 | 99篇 |
武器工业 | 47篇 |
无线电 | 1309篇 |
一般工业技术 | 400篇 |
冶金工业 | 83篇 |
原子能技术 | 33篇 |
自动化技术 | 2429篇 |
出版年
2024年 | 44篇 |
2023年 | 108篇 |
2022年 | 107篇 |
2021年 | 134篇 |
2020年 | 184篇 |
2019年 | 166篇 |
2018年 | 125篇 |
2017年 | 193篇 |
2016年 | 214篇 |
2015年 | 252篇 |
2014年 | 353篇 |
2013年 | 392篇 |
2012年 | 380篇 |
2011年 | 391篇 |
2010年 | 324篇 |
2009年 | 315篇 |
2008年 | 331篇 |
2007年 | 336篇 |
2006年 | 333篇 |
2005年 | 294篇 |
2004年 | 223篇 |
2003年 | 236篇 |
2002年 | 223篇 |
2001年 | 165篇 |
2000年 | 139篇 |
1999年 | 138篇 |
1998年 | 94篇 |
1997年 | 81篇 |
1996年 | 61篇 |
1995年 | 52篇 |
1994年 | 33篇 |
1993年 | 27篇 |
1992年 | 25篇 |
1991年 | 27篇 |
1990年 | 17篇 |
1989年 | 17篇 |
1988年 | 14篇 |
1987年 | 4篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 9篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1966年 | 1篇 |
1961年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有6592条查询结果,搜索用时 15 毫秒
1.
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
2.
3.
Vitamin D Compounds PRI-2191 and PRI-2205 Enhance Anastrozole Activity in Human Breast Cancer Models
Beata Filip-Psurska Mateusz Psurski Artur Anisiewicz Patrycja Libako Ewa Zbrojewicz Magdalena Maciejewska Micha Chodyski Andrzej Kutner Joanna Wietrzyk 《International journal of molecular sciences》2021,22(5)
1,25-Dihydroxycholecalciferol, the hormonally active vitamin D3 metabolite, is known to exhibit therapeutic effects against breast cancer, mainly by lowering the expression of estrogen receptors and aromatase activity. Previously, the safety of the vitamin D active metabolite (24R)-1,24-dihydroxycholecalciferol (PRI-2191) and 1,25(OH)2D3 analog PRI-2205 was tested, and the in vitro activity of these analogs against different cancer cell lines was studied. We determined the effect of the two vitamin D compounds on anastrozole (An) activity against breast cancer based on antiproliferative activity, ELISA, flow cytometry, enzyme inhibition potency, PCR, and xenograft study. Both the vitamin D active metabolite and synthetic analog regulated the growth of not only estrogen receptor-positive cells (T47D and MCF-7, in vitro and in vivo), but also hormone-independent cancer cells such as SKBR-3 (HER-2-positive) and MDA-MB-231 (triple-negative), despite their relatively low VDR expression. Combined with An, PRI-2191 and PRI-2205 significantly inhibited the tumor growth of MCF-7 cells. Potentiation of the antitumor activity in combined treatment of MCF-7 tumor-bearing mice is related to the reduced activity of aromatase by both An (enzyme inhibition) and vitamin D compounds (switched off/decreased aromatase gene expression, decreased expression of other genes related to estrogen signaling) and by regulation of the expression of the estrogen receptor ERα and VDR. 相似文献
4.
介绍了一种基于高性能浮点DSP芯片TMS320C32、CPLD芯片XC95288和A/D采样芯片AD976组成的多路采集系统的工作原理以及设计方法。通过对第一路施加特殊的电压量,在CCS开发环境下读取采样缓冲区的值,并利用Matlab对采样数据进行了全波傅氏变换。此外,该系统已在继电保护中得到广泛应用,实践表明,该系统能较好地解决多路模拟量的采集,并确保了采样数据的安全可靠性。 相似文献
5.
6.
Rui
Zhang Junmin Li Jianmin Jiao 《International Journal of Adaptive Control and Signal Processing》2020,34(7):919-936
This article investigates an adaptive fuzzy tracking control problem for a class of nontriangular form systems with asymmetric time-varying full state constraints. Unknown functions are approximated by the fuzzy logic systems. A domination approach is employed to tackle the nontriangular form structure. Time-varying asymmetric barrier Lyapunov functions (ABLFs) are adopted to ensure full-state constraints satisfaction. Based on the backstepping technique and time-varying ABLFs, an adaptive controller is proposed and guarantees that all the signals in the closed-loop system are ultimately bounded and the time-varying full state constraints are met. Simulation examples are presented to further demonstrate the effectiveness of the proposed approach. 相似文献
7.
讨论了输出终端带不等式约束情形的多输入多输出系统,说明了这些约束可以通过修改输入柔化系数而使其得以满足,在柔化系数的选择范围确定过程中,为了避免矩阵求逆,采用利用已知数据辨识参数的方法来确定柔化系数,从而使得问题简化。降低了计算量且加快了收敛速度。 相似文献
8.
9.
数模混合仿真中模拟信号的恢复及其误差对整个仿真过程具有重要影响。本文探讨了用零阶保持和一阶保持进行信号恢复的方法,比较了它们的误差及工作特点。特别指出了一阶保持中,由于存在积分器复原时间及数字机操作时间的影响而会带来附加的误差,因此一阶保持方法较难达到其理论的精度。 相似文献
10.
Generation of Technology-Independent Retargetable Analog Blocks 总被引:1,自引:0,他引:1
R. Castro-López F. V. Fernández F. Medeiro A. Rodríguez-Vázquez 《Analog Integrated Circuits and Signal Processing》2002,33(2):157-170
This paper introduces a complete methodology for retargeting of analog cells to different sets of specifications. This methodology is technology-independent, thus allowing the migration, from one technology to another, of the circuit under retargeting. Careful integration of the device sizing and layout generation tasks via the incorporation of layout constraints during the sizing process allows to generate fully functional designs in a few minutes. The methodology is illustrated via the retargeting of a fully-differential Miller-compensated two-stage operational amplifier for a new set of specifications and two different technological processes.An erratum to this article can be found at 相似文献