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51.
Ya. V. Terent’ev O. G. Lyublinskaya A. A. Toropov V. A. Solov’ev S. V. Sorokin A. A. Usikova S. V. Ivanov 《Semiconductors》2007,41(5):570-574
The electroluminescence and photoluminescence of bulk n-InAs with a high concentration of donors (N d ≈ 5 × 1016 cm?3) is studied experimentally in magnetic field in the Faraday layout of the experiment. Under the conditions of electrical injection, the photon energy corresponding to the electroluminescence peak exceeds the energy band gap E g. When a magnetic field is applied, the energy of the peak becomes lower than E g, and the peak splits into two circular-polarized components. The splitting depends on the injection current. In moderate magnetic fields (about 2 T), the splitting can be much more profound than the calculated splitting corresponding to the well-known g factor of electrons in InAs. The effect is attributed to different degrees of magnetic freezing-out of electrons with different spin orientation. The maximum in the dependence of the degree of polarization of photoluminescence on the magnetic field and the behavior of the photoluminescence line width support the model suggested. 相似文献
52.
I. L. Drichko A. M. D’yakonov I. Yu. Smirnov V. V. Preobrazhenskii A. I. Toropov 《Semiconductors》1999,33(8):892-897
The absorption and variation of the velocity of a surface acoustic wave of frequency f=30 MHz interacting with two-dimensional electrons are investigated in GaAs/AlGaAs heterostructures with an electron density
n=(1.3–2.8)×1011cm2 at T=1.5–4.2K in magnetic fields up to 7 T. Characteristic features associated with spin splitting of the Landau level are observed.
The effective g factor and the width of the spin-split Landau bands are determined: g*≅5 and A=0.6 meV. The greater width of the orbital-split Landau bands (2 meV) relative to the spin-split bands is attributed to different
shielding of the random fluctuation potential of charged impurities by 2D electrons. The mechanisms of the nonlinearities
manifested in the dependence of the absorption and the velocity increment of the SAW on the SAW power in the presence of spin
splitting of the Landau levels are investigated.
Fiz. Tekh. Poluprovodn. 33, 979–985 (August 1999) 相似文献
53.
S. V. Ivanov A. A. Toropov S. V. Sorokin T. V. Shubina I. V. Sedova P. S. Kop’ev Zh. I. Alferov A. Waag H. J. Lugauer G. Reuscher M. Keim F. F. Fischer G. Landwehr 《Semiconductors》1999,33(9):1016-1020
We report the results of an experimental study of molecular-beam epitaxy of ZnSe-based laser heterostructures with a new structure
of the active region, which contains a fractional-monolayer CdSe recombination region in an expanded ZnSe quantum well and
a waveguide based on a variably-strained, short-period superlattice are reported. Growth of a fractional-monolayer CdSe region
with a nominal thickness of 2–3 ML, i.e., less than the critical thickness, on a ZnSe surface (Δa/a∼7%) leads to the formation of self-organized, pseudomorphic, CdSe-enriched islands with lateral dimensions ∼10–30 nm and
density ∼2×1010 cm−2, which serve as efficient centers of carrier localization, giving rise to effective spatial separation of defective regions
and regions of radiative recombination and, as a result, a higher quantum efficiency. Laser structures for optical pumping
in the (Zn, Mg) (S, Se) system with a record-low threshold power density (less than 4 kW/cm2 at 300 K) and continuous-wave laser diodes in the system (Be, Mg, Zn) Se with a 2.5 to 2.8-ML-thick, fractional-monolayer
CdSe active region have been obtained. The laser structures and diodes have an improved degradation resistance.
Fiz. Tekh. Poluprovodn. 33, 1115–1119 (September 1999) 相似文献
54.
I. L. Drichko A. M. D’yakonov I. Yu. Smirnov Yu. M. Gal’perin V. V. Preobrazhenskii A. I. Toropov 《Semiconductors》2004,38(6):702-711
The complex high-frequency conductivity of GaAs/Al0.3Ga0.7As heterostructures that are δ-doped and modulation-doped with silicon was investigated by acoustic methods under conditions of the integer quantum Hall effect. Both the real (σ1) and imaginary (σ2) parts of the complex conductivity σ(ω, H)=σi?iσ2 were determined from the dependences of the absorption and velocity of surface acoustic waves on magnetic field. It is shown that, in the heterostructures with electron density ns=(1.3–7)×1011 cm?2 and mobility μ=(1–2)×105 cm2/(V s), the high-frequency conductivity near the centers of the Hall plateau is due to electron hopping between localized states. It is established that, with filling numbers 2 and 4, the conductivity of the Al0.3Ga0.7As:Si layer efficiently shunts the high-frequency hopping conductivity of the two-dimensional interface layer. A method of separating the contributions of the interface and Al0.3Ga0.7As:Si layers to the hopping conductivity σ(ω, H) is developed. The localization length of electrons in the interface layer is determined on the basis of the nearest neighbor hopping model. It is shown that, near the centers of the Hall plateau, both σ(ω, H) and ns depend on the cooling rate of a GaAs/Al0.3Ga0.7As sample. As a result, the sample “remembers” the cooling conditions. Infrared light and static strain also change both σ(ω, H) and ns. We attribute this behavior to the presence of two-electron defects (so-called DX? centers) in the Al0.3Ga0.7As:Si layer. 相似文献
55.
56.
Zinedine Khatir Joe PatonHarvey Thompson Nik KapurVassili Toropov Malcolm LawesDaniel Kirk 《Applied Energy》2012,89(1):89-96
Experimental and computational fluid dynamics (CFD) analyses of the thermal air flow distribution in a 3-zone small scale forced convection bread-baking oven are undertaken. Following industrial bread-making practise, the oven is controlled at different (constant) temperatures within each zone and a CFD model is developed and validated against experimental data collected within the oven. The CFD results demonstrate that careful selection of the flow model, together with implementation of realistic boundary conditions, give accurate temperature predictions throughout the oven. The CFD model is used to predict the flow and thermal fields within the oven and to show how key features, such as regions of recirculating flow, depend on the speeds of the impinging jets. 相似文献
57.
Identification of material parameters in constitutive model for sheet metals from cyclic bending tests 总被引:1,自引:0,他引:1
This paper deals with the identification of material parameters in a constitutive model for sheet metals using the bending moment versus curvature diagrams obtained by cyclic bending tests. The model can describe the cyclic strain hardening by the isotropic hardening and the Bauschinger effect by the kinematic hardening. An optimization technique based on the iterative multipoint approximation concept was used for the identification of the material parameters. This paper describes the experimentation, the fundamentals and the technique of the identification problem, and the verification of this approach. 相似文献
58.
I. A. Derebezov V. A. Haisler A. K. Bakarov A. K. Kalagin A. I. Toropov M. M. Kachanova T. A. Gavrilova A. S. Medvedev L. A. Nenasheva V. M. Shayakhmetov O. I. Semenova K. V. Grachev V. K. Sandyrev D. B. Tret’yakov I. I. Beterov V. M. Entin I. I. Ryabtsev 《Optoelectronics, Instrumentation and Data Processing》2009,45(4):361-366
A vertical-cavity surface-emitting laser on the basis of Al x Ga1 ? x As solid solutions is developed. The laser displays stable single-mode operation at a wavelength of 795 nm, which offers the prospects of its application in miniature chip-scale atomic clocks. 相似文献
59.
A. V. Gaisler A. S. Jaroshevich I. A. Derebezov A. K. Kalagin A. K. Bakarov A. I. Toropov D. V. Shcheglov V. A. Gaisler A. V. Latyshev A. L. Aseev 《Optoelectronics, Instrumentation and Data Processing》2013,49(5):498-503
Ensembles of InAs quantum dots with a very low density (~106 cm?2) are grown by molecular beam epitaxy, which allows the spectral characteristics of emission of single quantum dots to be studied by the method of cryogenic microphotoluminescence. With increasing quantum dot size, the splitting of exciton states is demonstrated to increase steadily to ~102 µeV. In the exciton energy range of 1.3–1.4 eV, the magnitude of this splitting is comparable with the natural width of the exciton lines. This result is important for the development of emitters of entangled photon pairs based on InAs quantum dots. 相似文献
60.