全文获取类型
收费全文 | 656篇 |
免费 | 44篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 15篇 |
化学工业 | 217篇 |
金属工艺 | 16篇 |
机械仪表 | 29篇 |
建筑科学 | 28篇 |
矿业工程 | 3篇 |
能源动力 | 40篇 |
轻工业 | 35篇 |
水利工程 | 25篇 |
石油天然气 | 10篇 |
无线电 | 46篇 |
一般工业技术 | 114篇 |
冶金工业 | 14篇 |
原子能技术 | 4篇 |
自动化技术 | 109篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 20篇 |
2021年 | 48篇 |
2020年 | 48篇 |
2019年 | 59篇 |
2018年 | 74篇 |
2017年 | 73篇 |
2016年 | 57篇 |
2015年 | 27篇 |
2014年 | 34篇 |
2013年 | 69篇 |
2012年 | 38篇 |
2011年 | 51篇 |
2010年 | 32篇 |
2009年 | 18篇 |
2008年 | 6篇 |
2007年 | 14篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有705条查询结果,搜索用时 15 毫秒
1.
Behrooz Safarinejadian Mojtaba Asad Mokhtar Sha Sadeghi 《International journal of control》2016,89(11):2277-2296
In the present paper, the identification and estimation problem of a single-input–single-output (SISO) fractional order state-space system will be addressed. A SISO state-space model is considered in which parameters and also state variables should be estimated. The canonical fractional order state-space system will be transformed into a regression equation by using a linear transformation and a shift operator that are appropriate for identification. The identification method provided in this paper is based on a recursive identification algorithm that has the capability of identifying the parameters of fractional order state-space system recursively. Another subject that will be addressed in this paper is a novel fractional order Kalman filter suitable for the systems with coloured measurement noise. The promising performance of the proposed methods is verified using two stable fractional order systems. 相似文献
2.
3.
4.
Wireless Networks - Vehicular ad hoc network (VANET), a special type of mobile ad-hoc networks (MANETs), is characterized by a very high mobility. Due to the dynamic nature of vehicle nodes and... 相似文献
5.
Mingfei Xiao Aditya Sadhanala Mojtaba Abdi-Jalebi Tudor H. Thomas Xinglong Ren Tao Zhang Hu Chen Remington L. Carey Qijing Wang Satyaprasad P. Senanayak Cameron Jellett Ada Onwubiko Maximilian Moser Hailiang Liao Wan Yue Iain McCulloch Mark Nikolka Henning Sirringhaus 《Advanced functional materials》2021,31(7):2007359
The measurement of the mechanical properties of conjugated polymers can reveal highly relevant information linking optoelectronic properties to underlying microstructures and the knowledge of the glass transition temperature (Tg) is paramount for informing the choice of processing conditions and for interpreting the thermal stability of devices. In this work, we use dynamical mechanical analysis to determine the Tg of a range of state-of-the-art conjugated polymers with different degrees of crystallinity that are widely studied for applications in organic field-effect transistors. We compare our measured values for Tg to the theoretical value predicted by a recent work based on the concept of effective mobility ζ. The comparison shows that for conjugated polymers with a modest length of the monomer units, the Tg values agree well with theoretically predictions. However, for the near-amorphous, indacenodithiophene–benzothiadiazole family of polymers with more extended backbone units, values for Tg appear to be significantly higher, predicted by theory. However, values for Tg are correlated with the sub-bandgap optical absorption suggesting the possible role of the interchain short contacts within materials’ amorphous domains. 相似文献
6.
Amir Amirabadi Mojtaba Chehelcheraghi Mahmoud Kamarei 《Circuits, Systems, and Signal Processing》2011,30(4):721-739
A third-order intermodulation cancelation technique using a non-linear feedback is proposed to design a low-power low-distortion
mixer in a 65 nm standard CMOS technology. The IM3 cancelation is achieved by estimating distorting error at a non-linear
feedback element and subtracting it from the input. The linearization technique is utilized in the input trans-conductance
of the mixer. The circuit functionality is analyzed using Volterra series. The covering frequency range of the mixer is 800 MHz
to 5 GHz. The technique increases the input-referred third-order intercept point (IIP3) and input 1 dB compression point to
+16.4 dBm and −1.87 dBm, respectively. It obtains a gain of 9 dB and an input-referred noise of 1.84 nV/?{}/\sqrt{}Hz while consumes 8.75 mA from 1.2 V supply. The layout of the mixer occupies 0.315 mm × 0.296 mm of silicon area. 相似文献
7.
Mojtaba Beheshti Mohammad Javad Omidi Ali Mohammad Doost-Hoseini 《Wireless Personal Communications》2013,71(2):1193-1215
Shallow underwater acoustic (UWA) channel exhibits rapid temporal variations, extensive multipath spreads, and severe frequency-dependent attenuations. So, high data rate communication with high spectral efficiency in this challenging medium requires efficient system design. Multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO–OFDM) is a promising solution for reliable transmission over highly dispersive channels. In this paper, we study the equalization of shallow UWA channels when a MIMO–OFDM transmission scheme is used. We address simultaneously the long multipath spread and rapid temporal variations of the channel. These features lead to interblock interference (IBI) along with intercarrier interference (ICI), thereby degrading the system performance. We describe the underwater channel using a general basis expansion model (BEM), and propose time-domain block equalization techniques to jointly eliminate the IBI and ICI. The block equalizers are derived based on minimum mean-square error and zero-forcing criteria. We also develop a novel approach to design two time-domain per-tone equalizers, which minimize bit error rate or mean-square error in each subcarrier. We simulate a typical shallow UWA channel to demonstrate the desirable performance of the proposed equalization techniques in Rayleigh and Rician fading channels. 相似文献
8.
Mojtaba Eslamnezhad Namin Mehdi Hosseinzadeh Nasour Bagheri Ahmad Khademzadeh 《Telecommunication Systems》2018,67(4):539-552
In radio frequency identification (RFID) systems, search protocols are used to find a specific item in a large number of tagged products. These protocols should be secure against RFID attacks such as traceability, impersonation, DoS and eavesdropping. Sundaresan et al. (IEEE Trans Dependable Secure Comput, 2015) presented a server-less search protocol based on 128-bits PRNG function and claimed that their method can address all vulnerabilities of previous protocols. In this paper, we prove that Sundaresan et al.’s protocol is vulnerable to traceability attack with the high probability. In addition, we present an improved protocol to solve the proposed problem and analyze its security level informally and formally based on AVISPA tool and BAN logic. 相似文献
9.
Water Resources Management - The unbridled increase in water demands and beyond-sustainable water withdrawals have led to decrease reliable supply levels, particularly for agricultural purposes in... 相似文献
10.
Gholamhossein Sodeifian Mojtaba Raji Morteza Asghari Mashallah Rezakazemi Amir Dashti 《中国化学工程学报》2019,27(2):322-334
SAPO-34 nanocrystals (inorganic filler) were incorporated in polyurethane membranes and the permeation properties of CO2, CH4, and N2 gases were explored. In this regard, the synthesized PU-SAPO-34 mixed matrix membranes (MMMs) were characterized via SEM, AFM, TGA, XRD and FTIR analyses. Gas permeation properties of PU-SAPO-34 MMMs with SAPO-34 contents of 5 wt%, 10 wt% and 20 wt% were investigated. The permeation results revealed that the presence of 20 wt% SAPO-34 resulted in 4.45%, 18.24% and 40.2% reductions in permeability of CO2, CH4, and N2, respectively, as compared to the permeability of neat polyurethane membrane. Also, the findings showed that at the pressure of 1.2 MPa, the incorporation of 20 wt% SAPO-34 into the polyurethane membranes enhanced the selectivity of CO2/CH4 and CO2/N2, 14.43 and 37.46%, respectively. In this research, PU containing 20 wt% SAPO-34 showed the best separation performance. For the first time, polynomial regression (PR) as a simple yet accurate tool yielded a mathematical equation for the prediction of permeabilities with high accuracy (R2 > 99%). 相似文献