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91.
Spectroscopic and scanning probe analysis on large-area epitaxial graphene grown under pressure of 4 mbar on 4H-SiC (0001) substrates 下载免费PDF全文
We produced epitaxial graphene under a moderate pressure of 4 mbar(about 400 Pa) at temperature 1600℃. Raman spectroscopy and optical microscopy were used to confirm that epitaxial graphene has taken shape continually with slight thickness variations and regularly with a centimeter order of magnitude on 4H-SiC(0001) substrates. Then using X-ray photoelectron spectroscopy and Auger electron spectroscopy, we analyzed the chemical compositions and estimated the layer number of epitaxial graphene. Finally, an atomic force microscope and a scanning force microscope were used to characterize the morphological structure. Our results showed that under 4-mbar pressure, epitaxial graphene could be produced on a SiC substrate with a large area, uniform thickness but a limited morphological property. We hope our work will be of benefit to understanding the formation process of epitaxial graphene on SiC substrate in detail. 相似文献
92.
The effect of substrate doping on the flatband and threshold voltages of a strained-Si pMOSFET 下载免费PDF全文
The effect of substrate doping on the flatband and threshold voltages of a strained-Si/SiGe p metal-oxide semiconductor field-effect transistor(pMOSFET) has been studied.By physically deriving the models of the flatband and threshold voltages,which have been validated by numerical simulation and experimental data,the shift in the plateau from the inversion region to the accumulation region as the substrate doping increases has been explained.The proposed model can provide a valuable reference to the designers of strained-Si devices and has been implemented in software for extracting the parameters of a strained-Si MOSFET. 相似文献
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用碘量法测定复杂含硒物料中常量硒并对测定条件做试验。试样经硝酸及硫酸溶解、蒸发至冒烟后,盐类溶于盐酸中。在酒石酸存在下加盐酸羟胺,于70℃保温1h,放置1.5h使硒还原为单质硒并陈化。过滤,将单质硒溶于盐酸中,溶解温度为90℃,溶解时间为5min,滴定时溶液酸度宜在0.2~0.5mol·L-1(盐酸介质)。滴定时采用分步滴加碘化钾溶液,随即用硫代硫酸钠标准溶液滴定至淀粉指示剂所显蓝色消失,至再次加入碘化钾无蓝色出现为终点。按所耗硫代硫酸钠标准溶液的体积计算试样的含硒量。 相似文献
94.
采用电子顺磁共振(ESR)和低温光致发光(PL)技术,研究了退火温度对低压化学气相沉积法(LPCVD)制备的非故意掺杂 4H-SiC材料中本征缺陷稳定性的影响.结果发现,当退火时间为10 min和30 min时,本征缺陷浓度均随着退火温度的升高而增大,当退火温度达到1573 K时材料中本征缺陷浓度达到最大,继续升高退火温度将使材料中本征缺陷浓度迅速降低.退火温度对材料中本征缺陷的影响主要是由于退火中本征缺陷的稳定化过程及本征缺陷之间发生强烈的相互作用引起的.
关键词:
高温退火
本征缺陷
电子顺磁共振谱
光致发光 相似文献
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Investigation of a 4H-SiC metal-insulationsemiconductor structure with an A1203/SiO2 stacked dielectric 下载免费PDF全文
Atomic layer deposited (ALD) Al2O3/dry-oxidized ultrathin SiO2 films as a high-k gate dielectric grown on 8° off-axis 4H-SiC (0001) epitaxial wafers are investigated in this paper. The metal-insulation-semiconductor (MIS) capacitors, respectively with different gate dielectric stacks (Al2O3/SiO2, Al2O3, and SiO2) are fabricated and compared with each other. The I-V measurements show that the Al2O3/SiO2 stack has a high breakdown field (≥12 MV/cm) comparable to SiO2, and a relatively low gate leakage current of 1 × 10-7 A/cm2 at an electric field of 4 MV/cm comparable to Al2O3. The 1-MHz high frequency C-V measurements exhibit that the Al2O3/SiO2 stack has a smaller positive flat-band voltage shift and hysteresis voltage, indicating a less effective charge and slow-trap density near the interface. 相似文献
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