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81.
从NEA GaAs光电阴极的激活光电流曲线发现,当系统真空度不很高时,在首次Cs激活阶段,表面掺杂浓度较低的阴极材料,其光电流产生需要的时间也较长.同时,随着系统真空度的提高,这种时间上的差异又变得不再明显.该现象表明,Cs原子在阴极表面的吸附效率同表面层掺杂浓度以及系统真空度之间有直接的联系.为定量分析这种关系,本文根据实验数据建立了Cs在阴极表面吸附效率的数学模型,利用该模型仿真的结果同实验现象非常符合.该研究对进一步开展变掺杂阴极结构设计和制备工艺研究具有重要的价值和意义.
关键词:
GaAs光电阴极
吸附效率
真空度
表面掺杂浓度 相似文献
82.
Dissipation of a two-mode squeezed vacuum state in the single-mode amplitude damping channel 下载免费PDF全文
We explore how a two-mode squeezed vacuum state sechθ ea+b+ tanh θ |00> evolves when it undergoes a singlemode amplitude dissipative channel with rate of decay κ. We find that in this process not only the squeezing parameter decreases, tanh θ → e-κt tanh θ, but also the second-mode vacuum state evolves into a chaotic state exp{b+bln[1 - e-2κt tanh2 θ]}. The outcome state is no more a pure state, but an entangled mixed state. 相似文献
83.
Xia Liu Hang Song Guoqing MiaoHong Jiang Lianzhen Cao Dabing LiXiaojuan Sun Yiren Chen 《Applied Surface Science》2011,257(6):1996-1999
In0.82Ga0.18As epilayers were grown on InP substrates using a two-step growth technique by LP-MOCVD. A homogeneous low-temperature (450 °C) In0.82Ga0.18As buffer layer was introduced to improve the crystalline quality of epilayers. The influence of low-temperature buffer layer deposition condition, such as thermal annealing duration, on the crystalline quality of the In0.82Ga0.18As epilayer was investigated. Double-crystal X-ray diffraction measurement, Hall measurement, and Raman scattering spectrum were used to evaluate the In0.82Ga0.18As epilayers. Atomic force microscope was used to study the surface morphology. It is found that the In0.82Ga0.18As epilayer, with buffer layer thermal annealing for 5 min, exhibits the best crystalline quality. The change of the surface morphology of the buffer layer after thermal annealing treatment was suggested to explain the phenomenon. 相似文献
84.
Alban A. Letailleur Sergey Yu Grachev Elin Søndergård Christophe Couteau Gilles Lérondel Emmanuelle Peter 《Journal of luminescence》2011,131(12):2646-2651
The application of alumina-doped ZnO (AZO) films as luminescent material for large area lighting sources has been evaluated. Thin films were grown on quartz using magnetron sputtering and subsequently annealed under argon atmosphere in a rapid thermal annealing experiment. Below 550 °C, red-shift of the optical band gap and increase of the visible emission are observed in agreement with Al diffusion and formation of interstitial oxygen atoms. At temperatures higher than 800 °C, diffusion is activated and Ostwald ripening leads to the formation of larger grains and an increase of the crystalline phase. The photoluminescence (PL) intensity is enhanced, specifically in the UV range. As a result the emission spectrum of AZO thin films can be adjusted by the annealing conditions, with equal contributions from the UV and orange parts of the PL spectrum resulting in an efficient white emission as quantified using the color space map of the Commission Internationale de l'Éclairage. 相似文献
85.
86.
The annealing process for boron implantation is a crucial step during large size nuclear radiation detector fabrication. It can reduce the lattice defects and the projection straggling. A two-step annealing process for boron implantation was developed instead of a one-step annealing process, and the reverse body resistance of a silicon micro-strip detector was significantly increased, which means that the performance of the detector was improved. 相似文献
87.
10 K条件下,采用光致发光(PL)技术研究了不同退火处理后非故意掺杂4H-SiC外延材料的低温PL特性.结果发现,在370—400 nm范围内出现了三个发射峰,能量较高的峰约为3.26 eV,与4H-SiC材料的室温禁带宽度相当.波长约为386 nm和388 nm的两个发射峰分别位于~3.21 eV和~3.19 eV,与材料中的N杂质有关.当退火时间为30 min时,随退火温度的升高,386 nm和388 nm两个发射峰的PL强度先增加后减小,且退火温度为1573 K时,两个发射峰的PL强度均达到最大.
关键词:
光致发光
退火处理
能级
4H-SiC 相似文献
88.
对熔体急冷法制备的Fe43Co43Hf7B6Cu1非晶合金进行了200,300,400和500 ℃保温30 min的退火处理,用正电子湮没寿命谱、X射线衍射、穆斯堡尔谱等方法研究了退火后试样的结构及结构缺陷变化.结果表明,在非晶合金的制备态,正电子主要在非晶基体相空位尺寸的自由体积中湮没,湮没寿命τ1为158.4 ps,强度I1关键词:
43Co43Hf7B6Cu1非晶')" href="#">Fe43Co43Hf7B6Cu1非晶
退火处理
正电子湮没寿命
结构与结构缺陷 相似文献
89.
Sandhya DwevediG. Markandeyulu P.R. OhodnickiAlex Leary M.E. McHenry 《Journal of magnetism and magnetic materials》2011,323(15):1929-1933
A systematic investigation of the influence of different types of annealing on the magnetoimpedance (MI) effect in melt-spun (Co1−xFex)89Zr7B4 [x=0, 0.025, 0.05] and (Co0.88Fe0.12)78.4Nb2.6Si9B9Al ribbons has been carried out in the frequency range 500 kHz-13 MHz and under dc magnetic fields (Hdc) up to 80 Oe. In the stress annealed ribbons, the strain-induced transverse anisotropy is seen to result in large MI. Magnetic domains were investigated in the ribbons through magnetic force microscopy. 相似文献
90.
Yue Zhao Mintao ZhouZhiyong Lv Zhao LiJian Huang Xiaoyan LiangJiahua Min Linjun Wang 《Superlattices and Microstructures》2011
Polycrystalline ZnO thin films codoped with Na and N were obtained by chemical bath deposition. The structural characteristic and the optical properties of the rapid thermal annealed ZnO:(Na,N) films were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer (EDS), Raman spectrum and room-temperature photoluminescence. After RTA treatment, the XRD spectra showed a continuous decrease of the full- width at half-maximum (FWHM) of the (0 0 2) diffraction peak of the ZnO:(Na,N) film. The Raman spectra revealed that the intensity of the mode around 582 cm−1 increased with the increase of the RTA temperature. The PL spectra showed different trends in the UV luminescence of ZnO:(Na,N) films after RTA treatments. 相似文献