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851.
852.
用自制常压MOCVD系统,在半绝缘GaAs衬底上生长高Al组份AlxGa1-xAs(其x值达0.83),和AlxGa1-xAs/GaAs/AlxGa1-xAs/GaAs多层结构,表面镜面光亮。生长层厚度从几十到十几μm可控,测试表明外延层晶格结构完整,x值调节范围宽,非有意掺杂低,高纯GaAs外延层载流子浓度n300K=1.7×1015cm-3,n77K=1.4×1015cm-3,迁移率μ300K=5900cmcm2/V.S,μ77K=55500cm2/V.S。用电子探针,俄歇能谱仪测不出非有意掺杂的杂质,各层间界面清晰平直。 对GaAs,AlGaAs生长层表面缺陷,衬底偏角生长温度及其它生长条件也进行了初步探讨。 相似文献
853.
Humberto Noverola-Gamas Luis Manuel Gaggero-Sager and Outmane Oubram 《中国物理 B》2022,31(4):44203-044203
The effects of the interlayer distance on the nonlinear optical properties of n-type quadruple δ-doped GaAs quantum well were theoretically investigated. Particularly, the absorption coefficient and the relative refraction index change were determined. In the effective mass approach and within the framework of the Thomas-Fermi theory, the Schrödinger equation was resolved. Thereby, the subband energy levels and their respective wave functions were calculated. The variations in the nonlinear optical properties were determined by using the density matrix solutions. The achieved results demonstrate that the interlayer distance causes optical red-shift on nonlinear optical properties. Therefore, it can be deduced that the suitably chosen interlayer distance can be used to tune optical properties within the infrared spectrum region in optoelectronic devices such as far-infrared photo-detectors, high-speed electronic-optical modulators, and infrared lasers. 相似文献
854.
855.
K. Shinohara Y. Shimizu S. Shimomura Y. Okamoto N. Sano S. Hiyamizu 《Physica E: Low-dimensional Systems and Nanostructures》1998,2(1-4)
Effectively atomically flat GaAs/AlAs interfaces over a macroscopic area (“super-flat interfaces”) have been realized in GaAs/AlAs and GaAs/(GaAs)
(AlAs)
quantum wells (QWs) grown on (4 1 1)A GaAs substrates by molecular beam epitaxy (MBE). A single and very sharp photoluminescence (PL) peak was observed at 4.2 K from each GaAs/AlAs or GaAs/(GaAs)
(AlAs)
QW grown on (4 1 1)A GaAs substrate. The full-width at half-maximum (FWHM) of a PL peak for GaAs/AlAs QW with a well width (
) of 4.2 nm was 4.7 meV and that for GaAs/(GaAs)
(AlAs)
QW with a smaller well width of 2.8 nm (3.9 nm) was 7.6 meV (4.6 meV), which are as narrow as that for an individual splitted peak for conventional GaAs/AlAs QWs grown on (1 0 0) GaAs substrates with growth interruption. Furthermore, only one sharp peak was observed for each GaAs/(GaAs)
(AlAs)
QW on the (4 1 1)A GaAs substrate over the whole area of the wafer (7
7 mm
), in contrast with two- or three-splitted peaks reported for each GaAs/AlAs QW grown on the (1 0 0) GaAs substrate with growth interruption. These results indicate that GaAs/AlAs super-flat interfaces have been realized in GaAs/AlAs and GaAs/(GaAs)
(AlAs)
QWs grown on the (4 1 1)A GaAs substrates. 相似文献
856.
857.
858.
利用计算光学性能、量子效率和积分灵敏度的理论模型,分别研究比较了我国和ITT典型透射式蓝延伸GaAs光阴极的光电发射特性,包括阴极的光学性质和性能参数。结果表明我国的透射式蓝延伸光阴极积分灵敏度已经达到2 100μA.lm-1,但与ITT的2 750μA.lm-1相比还存在一定的差距。分析的主要原因是一方面是GaAlAs窗口层的厚度和Al组分大小对于短波响应,特别是对蓝延伸起着决定的作用;另一方面阴极性能参数电子扩散长度和后界面复合速率的大小对长波响应和短波响应也有着重要的影响,这些因素都受制于基础工业制造水平的落后。 相似文献
859.
Structures,stabilities,and electronic properties of GaAs tubelike clusters and single-walled GaAs nanotubes 下载免费PDF全文
<正>The geometric structures,stabilities,and electronic properties of(GaAs)_n tubelike clusters at up to n=120 and single-walled GaAs nanotubes(GaAsNTs) were studied by density functional theory(DFT) calculations.A family of stable tubelike structures with a Ga-As alternating arrangement were observed when n≥8 and their structural units (four-membered rings and six-membered rings) obey the general developing formula.The average binding energies of the clusters show that the tubelike cluster with eight atoms in the cross section is the most stable cluster.The sizedependent properties of the frontier molecular orbital surfaces explain why the long and stable tubelike clusters can be obtained successfully.They also illustrate the reason why GaAsNTs can be synthesized experimentally.We also found that the single-walled GaAsNTs can be prepared by the proper assembly of tubelike clusters to form semiconductors with large band gaps. 相似文献
860.
We analyze the strain induced changes in the low temperature multisubband electron mobility mediated through the intersubband interactions in a pseudomorphic GaAs/InxGa1−xAs coupled double quantum well structure. We consider the non-phonon scattering mechanisms and study the effect of strain on them. We show that strain reduces the mobility due to ionized impurity (imp-) scattering μimp but enhances the mobility due to interface roughness (IR-) scattering μIR. For alloy disorder (AL-) scattering as long as the lowest subband is occupied, the effect of strain enhances the mobility μAL. However, once the second subband is occupied, there is almost no change, rather decrease in μAL for larger well widths. It is gratifying to note that for single subband occupancy, the effect of strain enhances the total mobility μ. On the other hand, for double subband occupancy, initially there is almost no change, but with increase in well width the total mobility reduces. We vary the In composition x from 0.15 to 0.2 and 0.25 and the barrier width between the two wells to analyze their effects on the mobility which shows interesting results. Our study of multisubband mobility can be utilized for the low temperature device applications. 相似文献