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101.
《Mathematical Methods in the Applied Sciences》2018,41(4):1377-1387
Under the displacement and stress satisfying Riemann boundary value condition, the decoupled quasistatic linear thermoelasticity system is discussed on bounded simply connected domain. The quasistatic equilibrium equation is solved by using Riemann boundary value problem theory. Also decoupled temperature equation is studied by applying the contractive mapping principle. Finally, existence and analyticity of the solution are proved. 相似文献
102.
In recent years, a great interest in the development of new broadband 1H homonuclear decoupled techniques providing simplified JHH multiplet patterns has emerged again in the field of small molecule NMR. The resulting highly resolved 1H NMR spectra display resonances as collapsed singlets, therefore minimizing signal overlap and expediting spectral analysis. This review aims at presenting the most recent advances in pure shift NMR spectroscopy, with a particular emphasis to the Zangger–Sterk experiment. A detailed discussion about the most relevant practical aspects in terms of pulse sequence design, selectivity, sensitivity, spectral resolution and performance is provided. Finally, the implementation of the different reported strategies into traditional 1D and 2D NMR experiments is described while several practical applications are also reviewed. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
103.
Thomas E Skinner M.Robin Bendall 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,134(2):315-330
A vector model of adiabatic decoupling is enunciated for an IS-coupled system of two spin- heteronuclei in the high-power limit of ideal adiabatic pulses. The observed S-spin magnetization evolves according to a time-dependent coupling that scales as thezcomponent of an I-spin vector which evolves due to the applied decoupling irradiation. Simple analytical expressions are derived both on and off resonance for the reduced coupling during an ideal sech/tanh inversion pulse and for the resulting signal when either in-phase or antiphase magnetization is present at the start of decoupling. The resulting model allows one to readily envision decoupling experiments, make accurate estimates of sideband intensity, and assess the relative performance of different decoupling schemes. The utility of the model is further demonstrated by applying it to several recently proposed methods for reducing sidebands. In the limit of ideal adiabatic pulses, the predictions of the vector model are almost identical to those of quantum mechanics. At the lower RF power levels used in practical adiabatic decoupling applications, where the pulses are no longer perfectly adiabatic, phase cycles are employed to achieve performance that approximates the ideal limits derived here, so the vector model is more generally applicable, as well. These limits establish standards for future determination of the most efficient parameters for practical applications of broadband adiabatic decoupling in a single transient. 相似文献
104.
证明了关于独立同分布随机变量序列的加权U-统计量的一个重对数律,类似于献「3」证明了一个加权U-统计量的解耦不等式。 相似文献
105.
Eric Hughes Eric B. Brouwer Robin K. Harris 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1999,138(2):256
For compounds giving “crowded” 1-dimensional magic-angle-spinning spectra, information about the local atomic environment in the form of the chemical shift anisotropy (CSA) is sacrificed for high resolution of the less informative isotropic chemical shift. Magic-angle-turning (MAT) NMR pulse sequences preserve the CSA information by correlating it to the isotropic chemical shift in a 2-dimensional experiment. For low natural abundance nuclei such as 13C and 15N and under 1H heteronuclear dipolar decoupling conditions, the dominant NMR interaction is the chemical shift. For abundant nuclei such as 1H, 19F, and 31P, the homonuclear dipolar interaction becomes a significant contribution to the observed linewidth in both F1 and F2 dimensions. We incorporate MREV8 homonuclear multiple-pulse decoupling sequences into the MAT experiment to give a multiple-pulse MAT (MP-MAT) experiment in which the homonuclear dipolar interaction is suppressed while maintaining the chemical shift information. Extensive use of computer simulation using GAMMA has guided the pulse sequence development. In particular, we show how the MREV8 pulses can be incorporated into a quadrature-detected sequence such as MAT. The MP-MAT technique is demonstrated for a model two-site system containing a mixture of silver trifluoroacetate and calcium difluoride. The resolution in the isotropic evolution dimension is improved by faster sample spinning, shorter MREV8 cycle times in the evolution dimension, and modifications of the MAT component of the pulse sequence. 相似文献
106.
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108.
首先介绍了距离-欺骗干扰的工作原理,利用干扰信号和目标回波的能量差别与起伏特性,以及多普勒频率的特性差异,提出了用于识别的特征因子,最后利用径向基网络进行识别分类。仿真结果表明,该方法有较高的识别率,切实可行。 相似文献
109.
Highly nonlinear advection–dispersion-reaction equations govern numerous transport phenomena. Robust, accurate, and efficient
algorithms to solve these equations hold the key to the success of applying numerical models to field problems. This paper
presents the development and verification of a computational algorithm to approximate the highly nonlinear transport equations
of reactive chemical transport and multiphase flow. The algorithm was developed based on the Lagrangian-Eulerian decoupling method with an adaptive ZOOMing and Peak/valley Capture (LEZOOMPC) scheme. It consists of both backward and forward node tracking, rough element determination, peak/valley
capturing, and adaptive local grid refinement. A second-order tracking was implemented to accurately and efficiently track
all fictitious particles. Shanks’ method was introduced to deal with slowly converging case. The accuracy and efficiency of
the algorithm were verified with the Burger equation for a variety of cases. The robustness of the algorithm to achieve convergent
solutions was demonstrated by highly nonlinear reactive contaminant transport and multiphase flow problems. 相似文献
110.