全文获取类型
收费全文 | 409篇 |
免费 | 26篇 |
专业分类
电工技术 | 11篇 |
综合类 | 2篇 |
化学工业 | 68篇 |
金属工艺 | 4篇 |
机械仪表 | 10篇 |
建筑科学 | 19篇 |
能源动力 | 49篇 |
轻工业 | 27篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 66篇 |
一般工业技术 | 100篇 |
冶金工业 | 24篇 |
原子能技术 | 1篇 |
自动化技术 | 50篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 14篇 |
2020年 | 20篇 |
2019年 | 15篇 |
2018年 | 16篇 |
2017年 | 23篇 |
2016年 | 26篇 |
2015年 | 4篇 |
2014年 | 23篇 |
2013年 | 33篇 |
2012年 | 25篇 |
2011年 | 34篇 |
2010年 | 27篇 |
2009年 | 38篇 |
2008年 | 32篇 |
2007年 | 22篇 |
2006年 | 11篇 |
2005年 | 14篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有435条查询结果,搜索用时 15 毫秒
11.
Jaroslav Koton Norbert Herencsar Kamil Vrba Bilgin Metin 《Analog Integrated Circuits and Signal Processing》2014,81(1):53-60
The paper focuses on the application possibilities of the newly presented voltage differencing active building block called voltage differencing differential difference amplifier. Using this active element, a multifunction frequency filter is designed featuring the possibility of mutually independent control of quality factor Q and characteristic frequency \(\omega _0\) by means of active elements. The structure of the filter is based on the idea of the Akerberg-Mossberg (AM) filter, i.e. the integrators in the structure are always realized only by two active elements. This fact results in better phase compensation for the filter. Compared to the AM opamp based filter, the newly proposed structure features high-impedance inputs, low-impedance output, and all basic frequency responses. The performance of the proposed structure has been verified by SPICE simulations using the TSMC \(0.18\,\upmu \hbox {m}\) level-7 SCN018 CMOS process parameters with \(\pm 0.9\,\hbox {V}\) supply voltage. 相似文献
12.
13.
14.
In this paper, we investigate the influence of hypercapnia on the early and late phases of the phrenic neurogram using the matching pursuit (MP) method in the decebrated piglets. The phrenic neurogram was recorded from 8 piglets (4-7 days old) during control (40% O2 with 5% end-tidal CO2), the mild hypercapnia (40% O2 with 7% end-tidal CO2), and the severe hypercapnia (40% O2 with 15% end-tidal CO2). The time-frequency representations, atoms, of the phrenic neurogram are calculated from the 5 consecutive phrenic neurogram burst for each piglet for each condition using the MP method after vagotomy and chemodenervation. Our results show that the energy percentage of atoms representing the nonperiodic neural activities (NPNAs) significantly increased when the CO2 concentration was shifted from 7% to 15% in the early phase (the first half) of the phrenic neurogram. In addition, the energy percentage of atoms representing the periodic neural activities (PNAs) decreased in the late phase (the second half) when the CO2 concentration was shifted from 7% to 15% (p < 0.01). As a summary, our result suggest that hypercapnia results in significant changes in the phrenic neurogram, an output of the respiratory neural networks in the medulla, both in time and frequency domians during early maturation. 相似文献
15.
16.
17.
In this paper, we present a multiuser detection technique based on artificial neural network (NN) for synchronous multicarrier code division multiple access systems over Rayleigh fading channels. To test the robustness of the proposed receiver, also the effect of power control problem is studied with a comparative manner. Bit error rate (BER) performance of the NN based receiver is compared with the single user bound and conventional receivers. Although the BER performance of the conventional receiver degrades as the number of the users and power level differences among the users increase, as a decision structure, neural network based receiver gives closer BER performance to the single user bound. 相似文献
18.
Metin Şengül 《AEUE-International Journal of Electronics and Communications》2013,67(8):676-680
To design broadband matching networks for microwave communication systems, commercially available computer aided design (CAD) tools are always preferred. But these tools need proper matching network topology and element values. Therefore, in this paper, a practical method is proposed to generate distributed-element matching networks with good initial element values. Then, the gain performance of the designed matching network can be optimized employing these tools. The utilization of the proposed method is illustrated by means of the given example. It is shown that proposed method provides very good initials for CAD tools. 相似文献
19.
Fırat Kaçar Bilgin Metin Hakan Kuntman Oguzhan Cicekoglu 《International Journal of Electronics》2013,100(5):499-510
In this article, a new complementary metal oxide semiconductor (CMOS) high-performance fully differential second-generation current conveyor (FDCCII) implementation is proposed. The presented FDCCII provides high-output impedance at terminals Z+ and Z?, good linearity and excellent output–input current gain accuracy. Also, the proposed FDCCII circuit operates at a supply voltage of ±1.3 V. The applications of the FDCCII to realise voltage-mode multifunction filters are given. Simulations are performed using TSMC CMOS 0.35-μm technology to verify theoretical results. 相似文献
20.
Wiklund U Akay M Morrison S Niklasson U 《IEEE transactions on bio-medical engineering》2002,49(7):651-661
In this paper, the discrete wavelet transform (DWT) was applied to analyze the fluctuations in RR interval and systolic arterial pressure (SAP) recorded from eight alpha-chloralose anesthetized pigs. Our aim was to characterize the autonomic modulation before and after cardiac autonomic blockade and during baroreflex function tests. The instantaneous power of decomposed low-frequency (LF) and high-frequency (HF) components was used for a time-variant spectral analysis. Our results suggested that transient events and changes in autonomic modulation were detected with high temporal resolution. A nonlinear relationship between RR interval and SAP during pharmacologically induced changes in blood pressure was found, when the superimposed effect of respiratory sinus arrhythmia was removed. In addition, the baroslopes were nearly linear when both the LF and HF components were removed using DWT decomposition. 相似文献