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91.
Guided by a Compton-sized model, we demonstrate that: (a) the magnetic self-energy of the electron, as estimated initially by Rasetti and Fermi, can be directly related to both the sign and the magnitude of the electron anomalous magnetic moment; and (b) the classical expression for the magnetic self-energy of the electron exhibits the same characteristic logarithmic divergence that occurs in QED. This electron model quantitatively reproduces the spin, magnetic moment, and gyromagnetic ratio of the electron, correct to first order in = e2 /c. It also relates the quantum-mechanical spin projection angle to the vanishing of the electric quadrupole moment, and it is capable of reproducing point-like scattering behavior.  相似文献   
92.
We present a number of molecular systems for which the average values 〈?2〉 before and after annihilation of the first spin contaminant in the wave function of the unrestricted Hartree-Fock method are anomalously large (they substantially exceed the expected value S (S + 1)). An example of such systems is N@C20, for the doublet state of which the 〈?2〉 values are equal to 4.2595 before and 13.1390 after annihilation, respectively (calculated by UHF/6-31G* method). We show that four, at the least, spin multiplets (S′ = S, S + 1, S + 2, S + 3) contribute comparatively to the wave function of such systems. The relations are derived allowing one to estimate the contributions of the highest multiplets basing on the average values of 〈?2〉 before and after annihilation of the first spin contaminant.  相似文献   
93.
The time evolution of a damped quantum particle is discussed. Dissipation is modeled by the bilinear coupling to a set of harmonic oscillators. Using a functional integral technique that accounts for initial correlations between the particle and the reservoir, one can express the dynamics of the damped particle entirely in terms of equilibrium correlation functions. The long-time behavior of these correlations is determined for memory damping arising from the coupling to a reservoir with spectral densityI() at low frequencies, where > 0. The time evolution of nonequilibrium initial states of the damped particle is discussed. At finite temperatures an initially localized state is found to spread subdiffusively or superdiffusively, depending on . For > 2 the damping becomes ineffective for long times, and the width of a state grows kinematically. At zero temperature and for < 1, an initially localized state remains localized for all times. For 1 the state spreads, but with a slower rate than at finite temperatures. Study of arbitrary initial states indicates that the process is ergodic at finite temperatures only for 2 and at zero temperature for 1 2.  相似文献   
94.
The crystal structure of air-dried crystals of the O-monocarboxylic acid of cyanocobalamin, E2, has been solved by x-ray analysis. The lattice constants area =14-51 A,b = 1709 A,c = 16.35A, β = 103°; space group P21. Phase angles were derived from observations on anomalous dispersion effects for 2567 of the measured 2875 pairs of reflections,hkl andhkl, and used in the solution of the structure. The intensities of reflexions were eye estimated from Weissenberg photographs. The molecular arrangement is very different from that of other cyanocobalamins; the corrin rings of neighbouring molecules are atca 90° to one another. It was not possible to recognise the one acid group among the amides with certainty.  相似文献   
95.
Many single-particle tracking data related to the motion in crowded environments exhibit anomalous diffusion behavior. This phenomenon can be described by different theoretical models. In this paper, fractional Brownian motion (FBM) was examined as the exemplary Gaussian process with fractional dynamics. The autocovariance function (ACVF) is a function that determines completely the Gaussian process. In the case of experimental data with anomalous dynamics, the main problem is first to recognize the type of anomaly and then to reconstruct properly the physical rules governing such a phenomenon. The challenge is to identify the process from short trajectory inputs. Various approaches to address this problem can be found in the literature, e.g., theoretical properties of the sample ACVF for a given process. This method is effective; however, it does not utilize all of the information contained in the sample ACVF for a given trajectory, i.e., only values of statistics for selected lags are used for identification. An evolution of this approach is proposed in this paper, where the process is determined based on the knowledge extracted from the ACVF. The designed method is intuitive and it uses information directly available in a new fashion. Moreover, the knowledge retrieval from the sample ACVF vector is enhanced with a learning-based scheme operating on the most informative subset of available lags, which is proven to be an effective encoder of the properties inherited in complex data. Finally, the robustness of the proposed algorithm for FBM is demonstrated with the use of Monte Carlo simulations.  相似文献   
96.
We briefly survey several typical CP-conserving two-Higgs-doublet models (2HDMs) in light of current experiments. First we derive the masses and couplings of the mass eigenstates from the Lagrangians. Then we analyze the constraints from theory and oblique electroweak parameters. Finally, we delineate the status of 2HDM in light of the LHC searches, the dark matter detections and the muon g − 2 measurement.  相似文献   
97.
98.
The phase behaviors of binary blends of poly(styrene‐b‐butadiene) block copolymers were investigated by a small‐angle X‐ray scattering technique. The blends were composed of weakly segregated one in a random micellar phase and the other in a cylindrical phase with similar molecular weights and complementary volume fractions. Morphologies, domain spacings, and order–disorder transition temperatures of the blends indicated that the junctions of the constituent block copolymers share the interface at low temperatures. The domain spacing decreased as temperature increased in a blend with a small amount of the weakly segregated block copolymer. In the cases of the blends with a large amount of the weakly segregated constituent, domain spacing increased with increasing temperature. These results implied that some of the weakly segregated block copolymer moved from the interface to one microdomain at higher temperatures. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 470–476  相似文献   
99.
In this study, we investigate Faraday rotation of electromagnetic waves that are anomalously transmitted through an over‐dense magnetized plasma layer. Here, magnetized plasma indicates that the plasma layer is immersed in a uniform magnetic field. Firstly, normally opaque over‐dense magnetized plasma is shown to be transparent to obliquely incident electromagnetic waves. This high transparency can be achieved by providing conditions for resonant excitations of plasmonic modes. The resonant characteristics of the transmission coefficient of the considered structure are determined and discussed. The conditions under which the magnetized plasma behaves as a complete reflector are also obtained. Faraday rotation is shown to be enhanced under high transparency conditions. The reflected wave also exhibits Faraday rotation and is enhanced under total reflection conditions. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
100.
刘桐君  习翔  令永红  孙雅丽  李志伟  黄黎蓉 《物理学报》2015,64(23):237802-237802
偏振不敏感超表面在实际应用中具有重要意义, 本文提出了一种光通信波段的、对偏振不敏感的异常反射式梯度超表面, 这种超表面对于x-偏振和y-偏振入射光都能够实现高效率的异常反射, 表现出偏振不敏感特性, 为解决传统反射式超表面的偏振敏感性问题提供了一种新途径. 它采用金属(Au)-绝缘层(SiO2)-金属(Au)结构, 超表面的超晶胞由五个各向同性的、尺寸不同的十字形基本结构单元组成. 仿真结果表明, 这种超表面结构对不同线偏振入射平面光波有几乎相同的相位和振幅响应; 合理的选取五个基本结构单元的尺寸, 在一个超晶胞内实现了2πup 相位的覆盖, 反射光波阵面畸变小, 而且反射光都集中到异常反射级次, 在工作波长1480 nm处具有较高的异常反射率(~ 70%). 此外, 这种结构的超表面在-30°–0°的宽入射角度范围内都具有偏振不敏感的异常反射特性. 在光通信、光信号处理、显示成像等领域具有潜在的应用前景.  相似文献   
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