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41.
Georgiou T Michailovich O Rathi Y Malcolm J Tannenbaum A 《Linear algebra and its applications》2007,425(2-3):663-672
The purpose of this paper is to describe certain alternative metrics for quantifying distances between distributions, and to explain their use and relevance in visual tracking. Besides the theoretical interest, such metrics may be used to design filters for image segmentation, that is for solving the key visual task of separating an object from the background in an image. The segmenting curve is represented as the zero level set of a signed distance function. Most existing methods in the geometric active contour framework perform segmentation by maximizing the separation of intensity moments between the interior and the exterior of an evolving contour. Here one can use the given distributional metric to determine a flow which minimizes changes in the distribution inside and outside the curve. 相似文献
42.
TLC Determination of Strychnine and Brucine of Strychnos nux vomica in Ayurveda and Homeopathy Drugs
Strychnos nux vomica is an important plant source for drugs of ayurvedic and homeopathic system of medicine. In this paper a thin layer chromatographic
(TLC) method has been developed for the quantitative estimation of the two major alkaloids strychnine and brucine in the plant
fruit and in ayurvedic and homeopathic drugs. Chloroform–ethyl acetate–diethyl amine (0.5:8.5:1) as mobile phase gave clear
separation with no interference between the bioactive markers. The R
f
values for strychnine and brucine were 0.55 and 0.42. The TLC method was found to be precise, rugged, robust and accurate
with recovery of strychnine in the range 93.11–99.82% and brucine 96.95–99.48%. The limit of detection (LOD) and limit of
quantification (LOQ) for strychnine were 1.9 and 8.25 ng and for brucine 2.2 and 9.2 ng respectively. 相似文献
43.
Ghule Balu Kakad Pandharinath Shirke Avantika Kotagale Nandkishor Rathi Lalit 《平面色谱法杂志一现代薄层色谱法》2021,34(2):131-138
JPC – Journal of Planar Chromatography – Modern TLC - A simple, reliable and reproducible high-performance thin-layer chromatography (HPTLC) method was established for determining... 相似文献
44.
The transformation of a simple disubstituted pyridine into a pyridinium ion bearing an exocyclic hydroxyl group, protected as a silane, enabled an intramolecular hydride transfer reaction to take place when fluoride was used as a nucleophile. The addition was both regio- and stereoselective and enabled the formation of enantiopure dihydropyridones when enantiopure pyridine derivatives were used in this sequence. The heterocyclic products contain ample functionality for further elaboration reactions and subsequent derivatization. 相似文献
45.
In this article, we have investigated the high-pressure structural phase transition of alkaline earth oxides using the three-body potential (TBP) model. Phase transition pressures are associated with elastic constants. An effective inter-ionic interaction potential (TBP) with long-range Coulomb interactions and the Hafemeister–Flygare type short-range overlap repulsion and the vdWl interaction is developed. The present calculations have revealed reasonably good agreement with the available experimental data on structural transition (B1–B2 structure). The phase transition pressures Pt of MgO, CaO, SrO, and BaO occur at 220, 45, 40, and 100?GPa, respectively. Further, the variations of the second-order elastic constants with pressure have followed a systematic trend, which are almost identical to those exhibited by the observed data measured for other semiconducting compounds with rocksalt (B1)-type crystal structure. It is found that TBP promises that we would be able to predict phase transition pressure and elastic constants for other chalcogenides as well. The results may be useful for geophysical study. 相似文献
46.
In life testing experiments, the skewed distributions like log-normal, Weibull, gamma and generalized gamma are the most suitable
models for recording the failure time measurements. In this paper, a generalized version of log-normal distribution is proposed
and its goodness-of-fit for a randomly censored data set representing the remission times of bladder cancer patients has been
demonstrated and compared with other lifetime models considered in the literature. The P-P plots of Kaplan-Meier estimator
against the survival functions of the considered models are used to show the goodness-of-fit. A simulation study is also performed
to estimate the parameters in both the classical and Bayesian setups. 相似文献
47.
N. Renuka N. Vijayan Brijesh Rathi R. Ramesh Babu K. Nagarajan D. Haranath G. Bhagavannarayana 《Optik》2012,123(3):189-192
In the recent past, nonlinear optical materials are getting attention in the field fibre optic communication and optical signal processing. In the present study, the title compound was successfully synthesized by conventional chemical reaction and then the single crystal was grown by slow evaporation solution growth technique. l-Arginine acetate (LAA) is semi organic non linear optical single crystal and crystallizes in noncentrosymmetric space group. The grown good quality single crystals have been analyzed by different characterization analyses such as powder X-ray diffraction, high resolution X-ray diffraction (HRXRD), Raman spectroscopy, photoluminescence, SEM, micro-hardness, thermal and birefringence analyses. 相似文献
48.
Alok Srivastava B. S. Bhadauria P. G. Siddheshwar I. Hashim 《Transport in Porous Media》2013,99(2):359-376
Thermo-rheological effect of temperature-dependent viscous fluid saturating a porous medium has been studied in the presence of imposed time periodic gravity field and internal heat source. Weak nonlinear stability analysis has been performed by using the power series expansion in terms of the amplitude of gravity modulation, which is considered to be small. Nusselt number is calculated numerically using Ginzburg–Landau equation. The nonlinear effects of thermo-mechanical anisotropies, internal heat source parameter, Vadász number, thermo-rheological parameter and amplitude of gravity modulation have been obtained and depicted graphically. Streamlines and isotherms have been drawn for different times. Comparisons have been made between various physical systems. 相似文献
49.
The effects of time-periodic boundary temperatures and internal heating on Nusselt number in the Bénard–Darcy convective problem has been considered. The amplitudes of temperature modulation at the lower and upper surfaces are considered to be very small. By performing a weakly non-linear stability analysis, the Nusselt number is obtained in terms of the amplitude of convection, which is governed by the non-autonomous Ginzburg–Landau equation, derived for the stationary mode of convection. The effects of internal Rayleigh number, amplitude and frequency of modulation, thermo-mechanical anisotropies, and Vadasz number on heat transport have been analyzed and depicted graphically. Increasing values of internal Rayleigh number results in the enhancement of heat transport in the system. Further, the study establishes that the heat transport can be controlled effectively by a mechanism that is external to the system. 相似文献
50.
The paper considers the flow of a power-law fluid past a vertical stretching sheet. Effects of variable thermal conductivity and non-uniform heat source/sink on the heat transfer are addressed. The thermal conductivity is assumed to vary linearly with temperature. Similarity transformation is used to convert the governing partial differential equations into a set of coupled, non-linear ordinary differential equations. Two different types of boundary heating are considered, namely Prescribed power-law Surface Temperature (PST) and Prescribed power-law Heat Flux (PHF). Shooting method is used to obtain the numerical solution for the resulting boundary value problems. The effects of Chandrasekhar number, Grashof number, Prandtl number, non-uniform heat source/sink parameters, wall temperature parameter and variable thermal conductivity parameter on the dynamics are shown graphically in several plots. The skin friction and heat transfer coefficients are tabulated for a range of values of the parameters. Present study reveals that in a gravity affected flow buoyancy effect has a significant say in the control of flow and heat transfer. 相似文献