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61.
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
62.
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
63.
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
64.
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
65.
小型稳压直流电源用铝电解电容器上机后有两种规格的电容器失效率高 ,且主要失效模式为开路。开路的根本原因是电容器高度超过允许安装高度。提出了从使用方法和生产工艺方面的解决措施 相似文献
66.
S C K Misra 《Bulletin of Materials Science》1987,9(1):67-72
All epitaxial gold-NaCl/NaBr-gold capacitors were fabricated on hot NaCl substrates. The dielectric properties, capacitance
and loss have been measured. Severe harmonic distortion in the output current has been observed. Maximum contribution was
from third and odd harmonics. The amplitude of harmonics was maximum at frequencies above the loss peak. The phenomenon has
been explained on the basis of nonlinear space charge theories. 相似文献
67.
A. Cuadras B. Garrido J. R. Morante L. Fonseca K. Pressel B. Tillack T. Grabolla 《Journal of Electronic Materials》2004,33(9):1022-1027
We describe and model the electrical response of interface states of metal-oxide semiconductor (MOS) capacitors fabricated
from Si1−x−yGexCy strained layers as a function of C concentration. We find that the introduction of Ge and C in the epilayers leads to anomalies
in the capacitance-voltage curves in the form of kinks or plateaus. This behavior is explained by the presence of pronounced
peaks on the density of interface states in the bandgap. Our results suggest an adequate Ge/C ratio of 40 minimizes the density
of interface states. This ratio is different from the ratio of ∼10 required for stress compensation. Finally, we discuss the
implications for the introduction of Si1−x−yGexCy strained layers to fabricate MOS devices. 相似文献
68.
采用改性的中和反应及热处理工艺合成了电化学电容器用无定形水合二氧化钌材料(RuO2·xH2O),并以高导电性石墨板作集流体,研究了合成材料的电化学性能。实验中,以自制的喷雾装置和十二烷基磺酸钠(SDS)分别作为反应辅助分散技术和表面分散剂。结果表明,合成材料的前驱体经175 ℃处理后,可获得大比表面积(218 m2/g)、蓬松状、深黑色无定形的高性能电极材料。循环伏安实验(CV)结果表明,该合成材料具有较好的比电容(995 F/g at 1mV/s)和倍率特性;电化学交流阻抗(EIS)实验进一步证明了该材料具有较低的等效串联内阻(~25 mΩ),同时验证了材料的倍率特性良好。合成材料有望在国防及民用领域电化学电容器中得到潜在应用 相似文献
69.
缓蚀剂在高压阳极箔电解扩孔中的作用机理 总被引:1,自引:0,他引:1
将高压阳极发孔铝箔在70℃、质量分数为3%的硝酸液中阳极电解扩孔,研究了添加大分子缓蚀剂聚苯乙烯磺酸(PSSA)后高压阳极箔的腐蚀机理。结果显示:添加PSSA后,腐蚀箔减薄量明显降低,质量损失率减小,并孔率降低,520 V化成的比容提高了约23%。隧道孔由孔口大、孔内小的"锥子"状转变为孔口小、孔内大的"垒球棒"状。铝箔表面的电位显著上升,而隧道孔内的电位基本保持不变,从而证明了,大分子缓蚀剂PSSA提高了铝箔表面和隧道孔口附近的电化学反应的阻力,电流主要分布到孔内,加速了孔内的扩孔过程。 相似文献
70.
MnO2 with novel mesoporous structure has been firstly synthesized via a simple in situ reduction process by using different carbon materials as sacrificed template and reducing agent. The morphology and microstructure of as-synthesized mesoporous MnO2 were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), nitrogen adsorption and desorption experiments. The results demonstrate that porous MnO2 prepared using mesoporous carbon as template has very large specific surface area and uniform pore-size distribution. The electrochemical measurements showed that novel porous MnO2 have higher capacity (221 F g−1) with excellent rate and higher capacity retention as electrochemical capacitors (ECs) electrode materials, which may be attributed to the unique nanostrcture of porous MnO2. These all imply that MnO2 with novel mesoporous structure has been attractive for practical and large-scale applications in mobile equipment. 相似文献