全文获取类型
收费全文 | 250篇 |
免费 | 13篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 14篇 |
综合类 | 1篇 |
化学工业 | 34篇 |
金属工艺 | 4篇 |
机械仪表 | 10篇 |
建筑科学 | 23篇 |
能源动力 | 6篇 |
轻工业 | 15篇 |
水利工程 | 5篇 |
石油天然气 | 8篇 |
无线电 | 65篇 |
一般工业技术 | 22篇 |
冶金工业 | 8篇 |
自动化技术 | 53篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 6篇 |
2020年 | 18篇 |
2019年 | 22篇 |
2018年 | 15篇 |
2017年 | 15篇 |
2016年 | 16篇 |
2015年 | 8篇 |
2014年 | 18篇 |
2013年 | 40篇 |
2012年 | 20篇 |
2011年 | 15篇 |
2010年 | 9篇 |
2009年 | 16篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 9篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 3篇 |
1999年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1983年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有268条查询结果,搜索用时 46 毫秒
21.
Behrouz Peikari 《Computers & Electrical Engineering》1978,5(4):293-297
This paper considers the problem of designing nonlinear multiport memoryless systems with prescribed driving point and transfer characteristics. It is shown that if the structure of the multiport system is given the input-output characteristics of the nonlinear elements can be obtained iteratively. This is achieved by implementation of a generalized steepest descent criterion. 相似文献
22.
Bilgin Metin Kirat Pal Shahram Minaei Oguzhan Cicekoglu 《Analog Integrated Circuits and Signal Processing》2009,60(3):205-213
Operational transconductance amplifiers (OTAs) are widely used in the design of electronically tunable circuits. However,
electronic tunability ranges of the OTA based filters are restricted by the limited bandwidth of the transconductance gain
of the OTA. Furthermore, stability conditions and the linearity of the OTA which depends on the control current restrict the
tunability. In this paper, some trade-offs in the electronically tunable filters are investigated. In addition, the tunability
ranges of some first and second order OTA-C and OTA-RC filters are comparatively examined. Moreover, an OTA-C all-pass filter
circuit is presented. SPICE simulations are performed and stability analyses are given for both of the OTA-C and OTA-RC filters.
Operation of the presented all-pass filter is verified experimentally. 相似文献
23.
Muhammed A. Ibrahim Shahram Minaei Erkan Yuce 《International Journal of Circuit Theory and Applications》2012,40(5):477-488
In this paper, two new circuit configurations for realizing voltage‐mode (VM) all‐pass sections (APSs) are presented. The proposed circuits employ only two differential voltage current conveyors (DVCCs) and are cascadable with other VM circuits due to their high‐input and low‐output impedances. The first configuration uses a grounded resistor and a grounded capacitor without requiring matching constraints, whereas the second employs two grounded resistors and a grounded capacitor with a single matching condition. While the first configuration can realize only one all‐pass response, the second can provide inverting and non‐inverting all‐pass responses with selection of appropriate input port. Adding two grounded resistors to the proposed filters, variable gain APSs can also be obtained. As applications, two quadrature oscillators, each of which using one of the proposed all‐pass circuits, one grounded resistor and one grounded capacitor are presented. SPICE simulation results are included to verify the theory. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
24.
Behrouz BEHNAM Fahimeh SHOJAEI Hamid Reza RONAGH 《Frontiers of Structural and Civil Engineering》2019,13(4):904
Investigating progressive collapse of tall structures under beam removal scenarios after earthquake is a complex subject because the earthquake damage acts as an initial condition for the subsequent scenario. An investigation is performed here on a 10 story steel moment resisting structure designed to meet the life safety level of performance when different beam removal scenarios after earthquake are considered. To this end, the structure is first subjected to the design earthquake simulated by Tabas earthquake acceleration. The beam removal scenarios are then considered at different locations assuming that both ends connections of the beam to columns are simultaneously detached from the columns; thus the removed beam falls on the underneath floor with an impact. This imposes considerable loads to the structure leading to a progressive collapse in all the scenarios considered. The results also show that the upper stories are much more vulnerable under such scenarios than the lower stories. Hence, more attention shall be paid to the beam-to-column connections of the upper stories during the process of design and construction. 相似文献
25.
26.
Mohammad Taghan Sasanpour Taheri Ali Movafeghi Amir Rokrok Behrouz 《Russian Journal of Nondestructive Testing》2019,55(12):967-974
Russian Journal of Nondestructive Testing - The purpose of this article is to determine the mathematical function of the optical behavior of radiographic films/images produced by gamma-ray... 相似文献
27.
Maysam Abbasi Ehsan Abbasi Behrouz Tousi Gevork B. Gharehpetian 《International Journal of Circuit Theory and Applications》2019,47(10):1630-1644
This paper presents a new step-up switched-capacitor (SC) DC-DC converter which has many advantages such as reduction in investment cost, control complexity, number of components, voltage stress on components, and size over traditional topologies. In the proposed structure, power switches are reduced in number which in turn leads to the merits mentioned earlier and makes the converter more suitable for industrial applications. Furthermore, a previously introduced zero-current switching (ZCS) method is used here which provides soft switching for the devices. There is also a reduction in the number of required inductors to achieve ZCS due to the decreased number of switches in the proposed converter. The proposed converter is validated by comprehensive simulation results in MATLAB Simulink environment and also precise experimental results which show the acceptable performance of the proposed topology. 相似文献
28.
Maryam Safarbeiranvnd Hakimeh Amanipoor Sedigheh Battaleb-Looie Kamal Ghanemi Behrouz Ebrahimi 《Water Resources Management》2018,32(11):3611-3628
In this research, based on the qualitative data of 40 wells, variations of water quality parameters of the Central Plain Aquifer were evaluated using kriging and IDW (Inverse Distance Weighting) methods. Owing to the normal distribution of the studied parameters (except Na+, SO42?, and TH: total hardness), ordinary kriging was used for modeling. The analysis of the data trends indicated that all the variables were influenced by in two general trends, i.e., NW–SE and NE–SW. In fact, these trends were a result of the effect of the structural conditions on aquifer properties such as transmissivity and flow direction. Variogram analysis (based on C0 near zero and C0/σ2 ratio between 0.0–0.5) showed that the Na+, TDS (total dissolved solids), Ca2+, and TH variables have a good spatial structure and the BOD (biochemical oxygen demand), COD (chemical oxygen demand), NO3?, and EC variables have poor spatial structure. The BOD, COD, NO3?, and EC (electrical conductivity) variables have the smallest range and isotropic distribution. On the other hand, the Ca2+, Mg2+, Na+, SO42?, Cl?, HCO3?, pH, TDS, TH and Alk (alkalinity) parameters are characterized by anisotropic distributions. The Na+, TDS, Ca2+, and TH variables have the largest range. The results showed that both the IDW and kriging methods have close estimates to one another. The pH variable decreases toward the outlet whereas the EC and TDS variables increase along the direction of water flow and toward the outlet. The distributions of the BOD and COD variables do not perfectly match with the aggregation of industrial activities in the central part as well as the agricultural activities in the southeastern and central parts of the aquifer. The distributions of the Ca2+, Mg2+, and Alk variables completely follow the geology condition and regional spread of carbonate formations. The Na+ concentration increases from the center toward the outlet. The concentration of the Cl? variable is the highest in the central part of the plain due to the concentration of agricultural and industrial activities. The distribution of the SO42? variable is influenced by a natural factor (lithology), especially in the southeastern parts and the outlet as well as artificial factors (agricultural and industrial activities) in the central and southeastern parts of the aquifer. The NO3? variable, which is directly influenced by agricultural and livestock-farming activities, has its maximum concentration in the southeastern areas. 相似文献
29.
This study investigates the forced vibration of functionally graded hexagonal
nano-size plates for the first time. A quasi-three-dimensional (3D) plate theory including
stretching effect is used to model the anisotropic plate as a continuum one where smallscale effects are considered based on nonlocal strain gradient theory. Also, the plate is
assumed on a Pasternak foundation in which normal and transverse shear loads are taken
into account. The governing equations of motion are obtained via the Hamiltonian
principles which are solved using analytical based methods by means of Navier’s
approximation. The influences of the exponential factor, nonlocal parameter, strain gradient
parameter, Pasternak foundation coefficients, length-to-thickness, and length-to-width
ratios on the dynamic response of the nanoplates are examined. In addition, the accuracy of
an isotropic approximate instead of the anisotropic model is studied. The dynamic behavior
of the system shows that mechanical mathematics-based models may get better results
considering the anisotropic model because the dynamic response can cause prominent
differences (up to 17%) between isotropic approximation and anisotropic model. 相似文献
30.
Jannesari Mohammad Mosaddegh Peiman Kadkhodaei Mahmoud Kasprzak Henryk Jabbarvand Behrouz Mahmoud 《Mechanics of Time-Dependent Materials》2019,23(3):373-384
Mechanics of Time-Dependent Materials - Non-contact tonometers, including ORA and Corvis ST, are not only used to estimate intraocular pressure (IOP) in clinical surveys but are also utilized to... 相似文献