全文获取类型
收费全文 | 172篇 |
免费 | 4篇 |
专业分类
电工技术 | 14篇 |
综合类 | 1篇 |
化学工业 | 43篇 |
金属工艺 | 8篇 |
机械仪表 | 1篇 |
建筑科学 | 4篇 |
能源动力 | 14篇 |
水利工程 | 7篇 |
无线电 | 22篇 |
一般工业技术 | 32篇 |
冶金工业 | 15篇 |
原子能技术 | 5篇 |
自动化技术 | 10篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 11篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 14篇 |
2012年 | 4篇 |
2011年 | 11篇 |
2010年 | 8篇 |
2009年 | 7篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 93 毫秒
31.
Fast algorithm for texture discrimination by use of a separable orthonormal decomposition of the co-occurrence matrix 总被引:1,自引:0,他引:1
We consider the problem of texture analysis with a fast algorithm. For that purpose we propose to use coefficients of the decomposition of co-occurrence matrices on an orthonormal and separable basis. We apply this method for texture discrimination, and we thus demonstrate with some examples its efficiency in terms of rapidity, discrimination performance, and robustness. We compare this method with classifiers that use a Fisher linear discrimination on features a priori defined in the co-occurrence matrices. 相似文献
32.
A. A. Hebeish A. A. Ragheb S. H. Nassar E. E. Allam J. I. Abd El Thalouth 《应用聚合物科学杂志》2006,102(1):338-347
The chemical modification of cotton fabric with reactive cyclodextrin (R‐CD) at different concentrations was carried out to enhance the printability of cotton fabric. The extent of the modification reaction was expressed as %N. Reactive and natural dyes were used to print cotton fabric before and after modification. Printing pastes were applied immediately after preparation or after 24 h of storage. Printing fixation was performed through either steaming or thermal treatment. The effect of the incorporation of R‐CD in the printing paste of unmodified cotton was also studied. The results reveal that the extent of the modification reaction increased with increasing R‐CD concentration and so did the color strength (K/S) of the printed sample regardless of the dye used. The results also revealed that K/S of the R‐CD modified cottons were higher than that of the corresponding unmodified samples regardless of the method of fixation or the time elapsed before printing. On the other hand, the incorporation of R‐CD in the printing pastes of reactive dyes, namely, Cibacron Brown 6R‐P or Remazol Brilliant Red GG, had adverse effects, most probability due to the (a) increasing viscosity of the paste and/or (b) interaction of the reactive dye with R‐CD hydroxyls. The opposite held true when a natural dye was used. Further, the incorporation of R‐CD in the printing pastes had no effect on the rheological type of the pastes or the on overall fastness properties of the prints. Nevertheless, such an incorporation of R‐CD was accompanied by a remarkable increase in the magnitude of the apparent viscosity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 338–347, 2006 相似文献
33.
A design of a log periodic SPIFA (spiral planar inverted-F antenna) is proposed. A way of tuning the SPIFA to work in the ISM band (2.45 GHz) is discussed. The purpose of the antenna is to detect any tumor in the liver depending on the change in the conductivity and the permittivity of the liver after being infected. Detecting liver cancer on its early stages will help in the treatment process and makes it much faster as cancer in early stages can be treated easily. The antenna is designed, simulated and measured in a rabbit's liver. The simulated and measured results show great agreement with each other. 相似文献
34.
Electrochemical techniques were used to investigate the effect of cysteine (cys) on the dissolution behavior of Cu10Ni alloy in sulfide-polluted salt water through the analysis of the alloy electrochemical behavior including Tafel polarization and electrochemical frequency modulation (EFM) along with scanning electron microscopy (SEM) and energy dispersive X-ray diffraction (EDX). The results showed that cys acts as a mixed type inhibitor. The dissolution rate decreases with increasing cys concentration and increases with increasing the temperature. An adherent layer of inhibitor molecules on the alloy surface is proposed to account for their inhibitive action. The adsorption of cys on the active cathodic sites was found to follow the Langmuir adsorption isotherm from which the thermodynamic parameters of adsorption and corrosion processes were determined and discussed. A synergistic effect was observed between cys and potassium iodide (KI). EFM data are in good agreement with SEM and EDX results. 相似文献
35.
A 2-D finite flement model was developed in this study to conduct a FE parametric study on the effects of some variables in the performance of geosynthetic reinforced soil integrated bridge system (GRS-IBS). The variables investigated in this study include the effect of internal friction angle of backfill material, width of reinforced soil foundation (RSF), secondary reinforcement within bearing bed, setback distance, bearing width and length of reinforcement. Other important parameters such as reinforcement stiffness and spacing were previously investgated by the authors. The performance of GRS-IBS were investgated in terms of lateral facing displacement, strain distribution along reinforcement, and location of potential failure zone. The results showed that the internal friction angle of backfill material has a significant impact on the performance of GRS-IBS. The secondary reinforcement, setback distance, and bearing width have low impact on the performance of GRS-IBS. However, it was found that the width of RSF and length of reinforcement have negligible effect on the performance of GRS-IBS. Finally, the potential failure envelope of the GRS-IBS abutment was found to be a combination of punching shear failure envelope (top) that starts under the inner edge of strip footing and extends vertically downward to intersect with Rankine active failure envelope (bottom). 相似文献
36.
Kholoud E. Salem Abdelrahman M. Mokhtar Ibrahim Soliman Mohamed Ramadan Basamat S. Shaheen Nageh K. Allam 《International Journal of Hydrogen Energy》2021,46(1):209-220
In this study, a considerable effort has been devoted for the synthesis of Ge-doped ZnO nanorods on FTO as an efficient and robust photoanode material for solar water splitting. A unique, optimized, and ultra-rapid fabrication method to produce uniform nanorods (30–70 nm in diameter) has been demonstrated using radio frequency sputtering followed by electrochemical anodization. The effect of Ge doping on the conductivity, charge carrier concentration, optical, and photoelectrochemical properties of ZnO was investigated using scanning electron microscope (SEM), glancing angle X-ray diffraction (GAXRD), UV–Vis spectrometer, and Mott Schottky analysis. Glancing angle XRD confirmed the presence of wurtzite structure with a preferable orientation around (101) plane, which is of particular interest for many applications. As evidenced by the photoelectrochemical and transient photocurrent measurements, the fabricated Ge-doped ZnO nanorods exhibited enhanced photocurrent (12 mA/cm2) with an exceptional open circuit voltage of ?1.07 VSCE (?0.416 VRHE) under AM1.5G illumination, compared to the undoped ZnO based-photoanodes. Moreover, the Ge-doped ZnO nanorods showed unprecedented photoconversion efficiency of 3.6% under AM1.5G illumination. Therefore, the fabricated Ge-doped ZnO nanorods could be a promising conductive photoanode for water splitting. 相似文献
37.
Bjorn De Sutter Osman Allam Praveen Raghavan Roeland Vandebriel Hans Cappelle Tom Vander Aa Bingfeng Mei 《Journal of Signal Processing Systems》2010,61(2):157-179
This paper presents a memory organization for SDR inner modem baseband processors that focus on exploiting ILP. This memory
organization uses power-efficient, single-ported, interleaved scratch-pad memory banks to provide enough bandwidth to a high-ILP
processors. A system of queues in the memory interface is used to resolve bank conflicts among the single-ported banks, and
to spread long bursts of conflicting accesses to the same bank over time. Bank address rotation is used to spread long bursts
of conflicting accesses over multiple banks. All proposed techniques have been implemented in hardware, and are evaluated
for a number of different wireless communication standards. For the 11a|n benchmarks, the overhead of stall cycles resulting
from unresolved bank conflicts can be reduced to below 2% with the proposed organization. For 3GPP-LTE, the most demanding
wireless standard we evaluated, the overhead is reduced to less than 0.13%. This is achieved with little energy and area overhead,
and without any bank-aware compiler support. 相似文献
38.
39.
Allam S.M. El-Khazendar M.A. Osheiba A.M. 《Energy Conversion, IEEE Transaction on》2007,22(3):584-591
This paper presents an analytical method for predicting the steady-state performance of a self-excited single-phase reluctance generator (SESPRG), which supplies R-- L load. The proposed analysis is based on the d--q axis model and phasor diagram of such a generator in the steady-state condition. Excitation capacitors are connected across both the main and auxiliary windings. Magnetic saturation is taken into account and is assumed to be confined to the direct axis, and is accounted for a variable direct-axis magnetizing reactance. Conditions of self-excitation and the minimum value of the capacitance required to achieve self-excitation are also given. Special attention is focused on the machine performance when it operates as a pure single-phase reluctance generator (PSPRG). A fixed-capacitor (FC) thyristor-controlled reactor (TCR) scheme is used to regulate the generator terminal voltage by controlling the thyristor conduction angle. Further stability limits are investigated by developing the active-reactive (P-Q) power diagram. Reasonably close agreement between the measured and predicted results is observed confirming the validity of the proposed analysis. 相似文献
40.
M.F. Allam 《International Journal of Electrical Power & Energy Systems》1980,2(3):123-128
A generalized state-estimation algorithm is derived using linear weighted least-squares theory and concepts of network solvability for any arbitrary distribution of given or measured variables. With a Lagrange tree, the power system state variables become the nodal, or busbar, voltages and the input data the measured line flows. The algorithm is stable and accurate in both static and tracking modes of operation, and a recursive method is suggested for its incorporation into an online state-estimator scheme involving bad data detection and identification and estimation of network configuration. 相似文献