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81.
We investigate theoretically the dynamics of three low-order transverse modes in a small-area vertical cavity surface emitting laser. We demonstrate the spontaneous breaking of axial symmetry of the transverse field distribution in such a device. In particular, we show that if the linewidth enhancement factor is sufficiently large dynamical regimes with broken axial symmetry can exist up to very high diffusion coefficients ~ 10 μm2/ns. 相似文献
82.
R.K. Bhan Raghvendra Sahai Saxena N.K. Saini L. Sareen R. Pal R.K. Sharma 《Infrared Physics & Technology》2011,54(5):379-381
Hg1−xCdxTe Metal–Insulator–Semiconductor (MIS) capacitors were studied both experimentally and theoretically to investigate the capacitance contributions due to band-to-band (btb) tunnelling and generation–recombination (gr) of carriers to inversion layer capacitance. A good fit to the data has been obtained by including the btb contributions rather than gr contributions. 相似文献
83.
Degrading the recombination activities of grain boundaries (GBs) is essential to improve the efficiency of multi‐crystalline silicon (mc‐Si) based solar cells. We apply the deep level transient spectroscopy technique to detect interface states at Σ3 and Σ9 GBs in mc‐Si. The density of interface states close to midgap is found comparable for both as‐grown GBs. Gettering or hydrogenation leads to shallower states with a smaller capture cross section and lower density. Recombination activity reduction for Σ3 GBs is stronger than for Σ9 GBs especially after hydrogenation. Both the analysis approach and experimental results could be applied for a specific GB engineering of mc‐Si based solar cells. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
84.
Chunying Pu Jiahui Yu Ling Fu Jia Wang Houyong Yang Dawei Zhou Chaozheng He 《中国化学快报》2021,32(3):1081-1085
Using the global particle-swarm optimization method and density functional theory,we predict a new stable two-dimensional layered material:MgSiP_2 with a low-buckled honeycomb lattice.Our HSE06 calculation shows that MgSiP_2 is an indirect-gap semiconductor with a band-gap of 1.20 eV,closed to that of bulk silicon.More remarkably,MgSiP2 exhibits worthwhile anisotropy along with electron and hole carrier mobility.A ultrahigh electron mobility is even up to 1.29 × 104 cm~2 V ~1 s ~1.while the hole mobility is nearly zero along the a direction.The large difference of the mobility between electron and hole together with the suitable band-gap suggest that MgSiP_2 may be a good candidate for solar cell or photochemical catalysis material.Furthermore,we explore MgSiP2 as an anode for sodium-ion batte ries.Upon Na adsorption,the semiconducting MgSiP2 transforms to a metallic state,ensuring good electrical conductivity.A maximum theoretical capacity of 1406 mAh/g,a small volume change(within 9.5%),a small diffusion barrier(~0.16 eV) and low average open-circuit voltages(~0.15 V) were found fo r MgSiP2 as an anode for sodium-ion batteries.These results are helpful to deepen the understanding of MgSiP2 as a nanoelectronic device and a potential anode for Na-ion batteries. 相似文献
85.
载气流速对高场不对称波形离子迁移谱的影响 总被引:2,自引:1,他引:2
载气流速是影响高场不对称波形离子迁移谱(FAIMS)的重要参数.以自制的高场不对称波形离子迁移谱仪为实验平台,在射频电场幅值3 kV/cm,频率500 kHz,占空比0.36的条件下,研究了载气流速对苯离子迁移谱谱峰强度和半峰宽的影响.实验结果表明: 载气流速为3.7 L/min时,苯样品的谱峰强度最大,仪器的灵敏度最高.随着载气流速的增加,谱峰半峰宽变宽,仪器的分辨率下降.载气流速为3 .0~3.7 L/min时仪器综合性能最佳.此结果对于控制迁移谱仪载气流速有重要的参考意义. 相似文献
86.
87.
Giuseppe Coppola Andrea Irace Giovanni Breglio Mario Iodice Luigi Zeni Antonello Cutolo Pasqualina M. Sarro 《Optics and Lasers in Engineering》2003,39(3):317-332
In this paper we describe two different kind of optoelectronic devices both based on a three terminals active device and exploit the plasma dispersion effect to achieve the desired working. The first device exploits this effect in order to obtain an optical modulation. The second device is an optoelectronic router based on the mode-mixing principle together with the injection-induced optical phase shift. Both devices are integrated into a Silicon on Silicon optical channel waveguide which can be realized using a standard bipolar process. The possibility of using standard, well-known technology presents several advantages with respect to III–V Optoelectronics. The active three terminal device used is a Bipolar Mode Field Effect Transistor (BMFET). Numerical simulation results are presented on both devices. 相似文献
88.
In this work,the KLL dielectronic recombination (DR) processes of highly charged He-like to O-like xenon ions are studied systematically by using a DR program,which is based on the multi-configuration Dirac-Fock (MCDF) method.The KLL DR resonant energies and the corresponding resonant strengths are calculated,emphasizing especially the effect of the Breit interaction on the DR strengths.The theoretical KLL DR spectra are obtained and compared with the latest experimental results obtained in the Shanghai Electron Beam Ion Trap. 相似文献
89.
90.
Silicon-rich hydrogenated amorphous silicon nitride (a-SiNx:H) films were grown by plasma enhanced chemical vapor deposition (PECVD) with different r=NH3/SiH4 gas flow ratios. The optical absorption characteristics were analyzed by Fourier transform infrared (FTIR) and UV-visible transmittance spectroscopies. The recombination properties were investigated via photoluminescence (PL) measurements. As r was increased from 2 to 9, the PL emission color could be adjusted from red to blue with the emission intensity high enough to be perceived by naked eye at room temperature. The behaviors of the PL peak energy and the PL band broadness with respect to the optical constants were discussed in the frame of electron-phonon coupling and band tail recombination models. A semiquantitative analysis supported the band tail recombination model, where the recombination was found to be favored when the carriers thermalize to an energy level at which the band tail density of states (DOS) reduces to some fraction of the relevant band edge DOS. For the PL efficiency comparison of the samples with different nitrogen contents, the PL intensity was corrected for the absorbed intensity fraction of the incident PL excitation source. The resulted correlation between the PL efficiency and the subgap absorption tail width further supported the band tail recombination model. 相似文献