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51.
Development of Ferroelectric Ceramics with High Dielectric Constant and Low Dissipation Factor for High-Voltage Capacitors 总被引:3,自引:0,他引:3
Both ferroelectric BaTiO3-based and SrTiO3-based dielectric ceramics with high dielectric constant and low dissipation factor have been successfully developed, and applied into mass production for high-voltage ceramic capacitors. Crystalline phases of the ceramics were identified by XRD. STEM study of the ceramics was also conducted. Based on the computer simulation of a shell-core and two-phase mixed structural model proposed, a novel processing method was employed to produce SrTiO3-based ceramics with the following satisfactory dielectric properties: dielectric constant at room temperature 20C=2000, dissipation factor at room temperature D
20C=0.003, temperature coefficient of dielectric constant = –8% (–25°C to 85°C), and, breakdown electric field E
b=10kV/mm(dc). Optional composition of BaTiO3-based ceramics has been obtained through the orthogonal design experimentation: BaTiO3-xBaZrO3-yBaSnO3, where x = 8wt% and y = 6wt%, with minor additions of MnSiO3, WO3, CeO2, Bi2(SnO3)3 and ZnO. Its major properties are as follows: Curie temperature T
c = 21°C, 20C=18,000, D
20'C = 0.008, =–80% (–25°C+85°C) and E
b = 8kV/mm (dc). 相似文献
52.
53.
Emmanuel Defaÿ David Wolozan Jean-Pierre Blanc Emmanuelle Serret Pierre Garrec Sophie Verrun Denis Pellissier Philippe Delpech Julie Guillan Bernard Andr Laurent Ulmer Marc Aïd Pascal Ancey 《Solid-state electronics》2007,51(11-12):1624
This paper describes realization and characterization of SrTiO3 (STO) high K MIM capacitors above BiCMOS integrated circuit (IC). These capacitances are connected to IC and are used as coupling capacitors in order to realize a high pass filter. Surface capacitance achieved is 10 nF/mm2 with capacitance value of 1.2 nF. The process for STO MIM fabrication does not exceed 400 °C, which is compatible with interconnections. Typical K and dielectric losses values obtained are, respectively 110% and 2%. Yield obtained reaches 83% for capacitors. A functional high pass filter using these STO capacitors was realized in this study. It exhibits a cut-off frequency at 6.5 kHz and a constant gain at higher frequencies of −1.3 dB. 相似文献
54.
对风电场并联电容器的投入过程进行了仿真研究。着重研究了投入电容器时的高频涌流及过渡电压降低的现象并提出了有效的改善措施。 相似文献
55.
This paper reports a ferroresonant experience involving inductive voltage transformers (VT's) in a 400 kV substation equipped with circuit breaker grading capacitors. Field measurements are presented and compared with ATP/EMTP simulation results, showing very good agreement. A parametric analysis has been performed to investigate the effect of the substation capacitance on the occurrence of ferroresonance. Fundamental frequency and sub-harmonic ferroresonant modes have been identified and compiled in a bifurcation diagram. The methodology presented can be used to create risk maps of avoidable switching operations or substation configurations. 相似文献
56.
An oxalate route for the production of BaTiO3 has been modified to incorporate Mn (upto 2%) as a dopant and the reaction sequence has been studied. The resulting Mn-doped
BaTiO3 exhibits a dielectric constant with an increasing insensitivity to temperature and applied a.c. field as the Mn content is
increased. These samples possess a high electrical resistivity even after treatment in hydrogen at 1100°C and are therefore
suitable as dielectric for multilayer capacitors with base metal electrodes. 相似文献
57.
It is known that stable hydrogen sensors can be made with palladium-aluminum oxidesilicon dioxide-silicon (PdMAOS) structures.
An improved way of making thin aluminum oxide films on silicon dioxide is presented. It is based on the oxidation of trimethylaluminum
in an argon/oxygen atmosphere at 300–400° C. The optical and electrical properties of Al2O3 films made with this metal-organic chemical vapor deposition (MOCVD) method are presented. Finally the properties of completed
PdMAOS hydrogen sensors are briefly presented. 相似文献
58.
A combination of step potential electrochemical spectroscopy (SPECS) and electrochemical impedance spectroscopy (EIS) has been used to examine the electrochemical cycling behaviour of a well-characterized birnessite-phase manganese dioxide sample for use in electrochemical capacitors. The resistance and interfacial properties of the macroscopic electrode were found to be irreversible with cycling. However, the corresponding properties for the individual particles were more reversible, although they did show substantial hysteresis in their behaviour during cycling. This behaviour was discussed in terms of the structural, conductivity and morphological characteristics of the birnessite at different depths of discharge. 相似文献
59.
In this study, the effect of measurement temperature and uniaxial drawing on the real (dielectric constant, ε′) and imaginary (loss index, ε″) parts of the complex dielectric constant of α‐crystalline phase poly(vinylidene fluoride) (PVDF) was investigated. The samples having different draw ratios (λ) were obtained by drawing the PVDF film at constant speed and temperature. The dielectric measurements were performed in the frequency range of 100 Hz–1 MHz and in the temperature range of 80–400 K. Although ε′ and ε″ were not affected by the orientation process during the β‐relaxation transition, it was observed that there were systematical variations for the α‐relaxation transition. ε′ and ε″ showed different behaviors depending on the draw ratio at different temperatures. Especially, ε″ was more affected by the orientation process at 380 K. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
60.
Amorphous tin oxide (SnOx) was cathodically deposited onto graphite electrode in a bath containing 0.1 M stannous chloride (SnCl2), 0.5 M sodium nitrate (NaNO3), and 0.4 M nitric acid (HNO3) in an aqueous solution of 50% (v/v) ethanol. The SnOx coatings grown on graphite were characterized as typical capacitive behaviors by cyclic voltammetry (CV), chronopotentiometric (CP) in 0.5 M KCl. Specific capacitance (in milli-farad per square centimeter, Ca) changes linearly with the deposition charge up to 4.5 C cm−2, and a maximum of as high as 355 mF cm−2 was obtained with the SnOx coating grown at around 5 C cm−2. For the SnOx coating deposited at 0.2 C cm−2, a maximum specific capacitance (in farad per gram, Cm) of 298 and 125 F g−1 was achieved from CVs at a scan rate of 10, and 200 mV s−1, respectively. The value of Cm significantly gets lower from 265 to around 95 F g−1 when the deposition charge increases from 0.2 to around 6.0 C cm−2. The long cycle-life and stability of the SnOx coatings on graphite via the presented cathodic deposition were also demonstrated. 相似文献