全文获取类型
收费全文 | 190篇 |
免费 | 5篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 44篇 |
金属工艺 | 7篇 |
机械仪表 | 18篇 |
建筑科学 | 2篇 |
矿业工程 | 1篇 |
能源动力 | 13篇 |
轻工业 | 4篇 |
无线电 | 14篇 |
一般工业技术 | 50篇 |
冶金工业 | 7篇 |
自动化技术 | 31篇 |
出版年
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 1篇 |
2014年 | 11篇 |
2013年 | 28篇 |
2012年 | 15篇 |
2011年 | 19篇 |
2010年 | 10篇 |
2009年 | 20篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有195条查询结果,搜索用时 46 毫秒
91.
Radu Banica Paul Barvinschi Nicolae Vaszilcsin Terezia Nyari 《Journal of Alloys and Compounds》2009,483(1-2):402
Molybdenum oxides thin films electrochemical deposition was performed using solutions of peroxo-polymolybdate at pH 2.3 and ammonium molybdate at pH 5.5 as precursors and smooth copper and platinum as supports. The deposition has been carried out at constant potentials in the range of −600 to −800 mV vs. Ag/AgCl (sat. KCl). The thin films deposited on copper were then heated at 350 and 450 °C in argon. In the case of thin films deposited from ammonium molybdate and heated at 450 °C, the XRD spectra reveal, along with MoO2, the presence of Cu6Mo5O18 phase. For the thin films prepared from peroxo-polymolybdate and subjected to the same heat treatment, the only XRD phase present was MoO2. Thermogravimetric (TG) analysis was performed on samples prepared by scraping away the thin films (molybdate precursors) from the copper support. Before heat treatment, the AFM images of the as-deposited thin film reveal a granular morphology, with diameters in the 20–80 nm range. 相似文献
92.
V. Babin M. Popescu M. Ciobanu N. D. Nicolae C. Talianu G. Ciuciu 《Journal of Materials Science: Materials in Electronics》2006,17(4):307-314
It is proposed a quasi-linear algorithm for the solving the kinetic equations system, which describes the excitation and relaxation
processes in the electronic and phononic subsystems of amorphous chalcogenides. The nonlinear interaction between an optical
field and an amorphous chalcogenide medium is analyzed. The nonlinear interaction between an excitation incident optical field
and the non-crystalline chalcogenide materials, evidences the specific nonlinear phenomena in amorphous semiconductors, which
have no correspondent in the case of crystalline semiconductors. The model is limited to phenomena occurring in chalcogenide
semiconductors, simultaneously with the optical field propagation, by neglecting the excitation phenomena. 相似文献
93.
Tamara Slatineanu Mircea Nicolae Palamaru Ovidiu Florin Caltun Liviu Leontie 《Materials Research Bulletin》2011,46(9):1455-1460
Nanocrystalline powders of nickel substituted zinc ferrite with general formula NixZn1−xFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) have been synthesized via sol-gel auto-combustion method using tartaric acid as combustion-complexing agent. Samples were sintered at 773 K and 973 K in static air atmosphere. The absence of the organic phase and the spinel formation were monitored by using Fourier transform infrared spectroscopy. The structure and crystallite size were analyzed from X-ray diffraction data revealing spinel mono-phase formation in the range of nanometric crystallite size confirmed also through scanning electron microscopy. Mean size of crystallites lay in the range 20-40 nm. The influence of nickel content on the microstructure was investigated considering the crystallite size, distance between adjacent crystal planes, lattice parameter and porosity. The variation of magnetic properties of the samples was studied by using vibrating samples magnetometer and discussed considering the proposed cation distribution, relative bond angles and canting angles. The highest maximum value of the magnetization (63 emu/g) was found for Ni0.8Zn0.2Fe2O4. 相似文献
94.
Hae‐Ryong Kim Alexander Haensch Il‐Doo Kim Nicolae Barsan Udo Weimar Jong‐Heun Lee 《Advanced functional materials》2011,21(23):4456-4463
The humidity dependence of the gas‐sensing characteristics in SnO2‐based sensors, one of the greatest obstacles in gas‐sensor applications, is reduced to a negligible level by NiO doping. In a dry atmosphere, undoped hierarchical SnO2 nanostructures prepared by the self‐assembly of crystalline nanosheets show a high CO response and a rapid response speed. However, the gas response, response/recovery speeds, and resistance in air are deteriorated or changed significantly in a humid atmosphere. When hierarchical SnO2 nanostructures are doped with 0.64–1.27 wt% NiO, all of the gas‐sensing characteristics remain similar, even after changing the atmosphere from a dry to wet one. According to diffuse‐reflectance Fourier transform IR measurements, it is found that the most of the water‐driven species are predominantly absorbed not by the SnO2 but by the NiO, and thus the electrochemical interaction between the humidity and the SnO2 sensor surface is totally blocked. NiO‐doped hierarchical SnO2 sensors exhibit an exceptionally fast response speed (1.6 s), a fast recovery speed (2.8 s) and a superior gas response (Ra/Rg = 2.8 at 50 ppm CO (Ra: resistance in air, Rg: resistance in gas)) even in a 25% r.h. atmosphere. The doping of hierarchical SnO2 nanostructures with NiO is a very‐promising approach to reduce the dependence of the gas‐sensing characteristics on humidity without sacrificing the high gas response, the ultrafast response and the ultrafast recovery. 相似文献
95.
Iuliana Stoica Luiza Epure Ion Sava Victor Damian Nicolae Hurduc 《Microscopy research and technique》2013,76(9):914-923
The surface morphology of azo‐polyimide films was investigated after 355nm Nd: YAG laser irradiation with two different incident fluencies. Atomic force microscopy (AFM) was employed to correlate the laser‐induced tridimensional nanogrooved surface relief with the incident fluence and the number of irradiation pulses. The height images revealed that the grooves depth increased even tens of times by increasing the incident fluence, using the same numbers of irradiation pulses. For low incident fluence, the films were uniformly patterned till 100 pulses of irradiation. Instead, when using higher fluence, after 15 pulses of irradiation the accuracy of the surface relief definition was reduced. This behavior could be explained by means of two different mechanisms, one that suppose the film photo‐fluidization due to the cis‐trans isomerization processes of the azo‐groups and the second one responsible for the directional mass displacement. The dominant surface direction and parameters like isotropy, periodicity, and period were evaluated from the polar representation for texture analysis, revealing the appearance of ordered and directionated nanostructures for most of the experimental conditions. Also, the graphical studies of the functional volume parameters have evidenced the improvement of the relief structuration during surface nanostructuration. The correlation of these statistical texture parameters with the irradiation characteristics is important in controlling the alignment of either the liquid crystals or the cells/tissues on patterned azo‐polyimide surfaces for optoelectronic devices and implantable biomaterials, respectively. Microsc. Res. Tech. 76:914–923, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
96.
Elena-Luiza Epure Ioana Andreea Moleavin Elena Taran Anh V. Nguyen Norica Nichita Nicolae Hurduc 《Polymer Bulletin》2011,67(3):467-478
The photo-fluidization process which is specific for azo-materials opens a new perspective for their use in the field of molecules
nano manipulation at the surface of the azo polymer films. This is possible considering that in the case of the UV irradiation
from a polarized laser source the azo material has an unidirectional flow. Here, we investigated the structuring phenomena
occurring on the surface of the azo-polysiloxanes films modified with nucleobases, upon UV irradiation. Measurements of topography
and adhesive forces between polymeric substrates and a hydrophilic probe have been done by atomic force microscopy (AFM).
The response of the material upon irradiation has been investigated also by using UV−VIS spectroscopy. This method allowed
us to draw the photo-isomerization and relaxation curves. Also, preliminary tests were conducted to determine the capacity
of the film surface to immobilize DNA molecules. 相似文献
97.
Dragos Nicolae Vizireanu Simona Viorica Halunga 《International Journal of Electronics》2013,100(1):149-151
In this note, we show that the amplitude estimation of sinusoidal signals proposed in Wu and Hong [Wu, S.T., and Hong, J.L. (2010), ‘Five-point Amplitude Estimation of Sinusoidal Signals: With Application to LVDT Signal Conditioning’, IEEE Transactions on Instrumentation and Measurement, 59, 623–630] is a particular case of Vizireanu and Halunga [Vizireanu, D.N, and Halunga, S.V. (2011), ‘Single Sine Wave Parameters Estimation Method Based on Four Equally Spaced Samples’, International Journal of Electronics, 98(7), pp. 941–948]. An analytical formula for amplitude estimation errors as effects of sampling period deviation is obtained. 相似文献
98.
Violeta Elena Copcia Camelia Luchian Simona Dunca Nicolae Bilba Claudia Mihaela Hristodor 《Journal of Materials Science》2011,46(22):7121-7128
The aim of the present work was to estimate the bactericidal activity and efficacy of silver pre-treated clinoptilolite-rich
tuff from Marsid (Romania) in solid media (agar plates) against Gram-negative Escherichia coli ATCC 25922 and Gram-positive Staphylococcus aureus ATCC 25923. Two samples of natural clinoptilolite-rich tuff was first pre-treated with oxalic acid and sodium hydroxide solutions,
respectively. The sample treated with oxalic acid was then exchanged with sodium chloride solution to obtain sodium form.
Finally, both samples were exchanged with silver nitrate solution at room temperature for 24 h to obtain silver forms (P1-Ag+ and P2-Ag+) of clinoptilolite. The structure, morphology, and elemental composition of the pre-treated clinoptilolite samples were characterized
by XRD, infrared (ATR-IR), SEM, and EDX analysis. The antibacterial activity was investigated by exposing E. coli and S. aureus in nutritive agar to the silver-clinoptilolite samples. Microorganisms were completely inhibited at 2 mg Ag+-clinoptilolite/mL nutritiv medium after 24 h of incubation at 37 °C. The silver-clinoptilolite sample derived from natural
clinoptilolite pre-treated with oxalic acid (P1-Ag+) exhibit a stronger antibacterial effect in the presence of E. coli and the sample derived from natural clinoptilolite pre-treated with sodium hydroxide (P2-Ag+) in the presence of S. aureus. 相似文献
99.
A fast,simple and accurate time-varying frequency estimation method for single-phase electric power systems 总被引:4,自引:0,他引:4
This paper presents a simple and accurate method to estimate time-varying frequency for single-phase electric power systems, based on three equally spaced samples. A sinusoidal voltage signal model, without dc offset, with time-varying frequency was assumed. Analytical formulas are derived. The method shows good estimation accuracy over a real world wide range of frequency changes. Simulations have been performed. 相似文献
100.
提高粉状物料造球效果的技术措施是基于对微造球机理的认识。假定了基于第一中心和第二中心的两种微造球机理。为了描述和解释原料粒度结构组成对微造球机理的影响,定义了两个新参数,即N1和N2两个比率,并介绍了关于N1、N2重要性的的试验结果和相关技术措施。 相似文献