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81.
In this paper we examine the power-series development with respect to Poisson's ratio of the solution to the second boundary-value problem (surface tractions prescribed) in three-dimensional classical elastostatics for the case of vanishing body forces. The individual terms of this expansion, by means of steady-state thermoelasticity theory, are found to admit an independent physical interpretation. This interpretation, in turn, permits certain conclusions concerning the dependence upon the elastic constants of solutions to space problems. In particular, it is shown that for a body of arbitrary connectivity all stresses are independent of the elastic constants if and only if the dilatation (and the mean normal stress) is a linear function of the cartesian coordinates. The feasibility of successive approximations of solutions appropriate to sufficiently small values of Poisson's ratio is also considered.The results communicated in this paper were obtained in the course of an investigation conducted under Contract Nonr 562(25) of Brown University with the Office of Naval Research, Washington, D.C. 相似文献
82.
Amiya Kumar Panda Phil Wojciechowski Kaushik Nag Fred Possmayer Nils O. Petersen 《Journal of Dispersion Science and Technology》2013,34(9):1255-1261
Studies on the interaction of cholesterol (CHOL) with palmitoyl-oleoyl phosphatidylcholine (POPC) and sphingomyelin (SPM) are considered to be important because of the occurrence of strong interactions between sphingolipids and CHOL, which lead to the formation of microdomains or rafts within biological membranes. In the present investigation, studies on the surface pressure (π)-area ( A ) measurements and fluorescence microscopic studies on monolayers of the above mentioned system have been reported. Ideality/nonideality of mixing, excess area, and free energy changes during the formation of the monolayers at different surface pressures for the mixed lipid systems were evaluated from the π– A data. Interactions were found to be repulsive at lower CHOL content, which became associative at higher CHOL content. Condensing effects of CHOL on the mixed monolayers were found. Fluorescence studies on the systems revealed similar overall results. 相似文献
83.
84.
Toshiatsu Oda Utarō Furukane 《Journal of Quantitative Spectroscopy & Radiative Transfer》1983,29(6):553-559
Overpopulation densities Δnitij, which are defined as the differences between the population densities per unit statistical weight of the upper and lower excited levels i and j, are calculated as a function of the electron density ne for various electron temperatures Te in recombining hydrogen plasmas. Calculation have been made for line pairs with principal quantum numbers (2 ,3), (3, 4) and (4, 5). The effect of the ground-level population density n1 on Δnij is calculated. In this calculation, the atom-atom collision and the self-absorption of the resonance lines are taken into account. The n1-dependence of Δnij remains almost constant until the self-absorption becomes significant. The threshold condition for laser oscillation is discussed in relation to the calculated Δnij. Laser oscillation is possible for the line pair (2, 3) at an electron density and temperature higher than for the other pairs (3, 4) and (4, 5) when self-absorption is negligible. 相似文献
85.
86.
Utarō Furukane Toshiaki Yokota Toshiatsu Oda 《Journal of Quantitative Spectroscopy & Radiative Transfer》1979,22(3):239-245
The collisional-radiative model is applied to a recombining hydrogen plasma in order to investigate plasma conditions in which a population inversion between the energy levels of hydrogen can be generated. Population inversion is expected in plasmas for which three-body recombination makes a large contribution to the recombining processes and the effective recombination rate is larger than a critical value for a given electron density and temperature. Calculated results are presented in figures and tables. 相似文献
87.
88.
Utarō Furukane Yasumasa Tsuji Toshiatsu Oda 《Journal of Quantitative Spectroscopy & Radiative Transfer》1982,27(5):557-562
Plasma conditions for generating a population inversion between the ground and first excited states in a recombining hydrogen plasma have been investigated on the basis of the CR model. Population inversion can be expected when three-body recombination plays a dominant role; the required regions of electron density and temperature are specified. It is shown that upper bounds exist for the ground-state population density at given electron density and temperature. Larger inversion densities can be obtained between the ground and first excited states than between excited levels. Numerical results are presented. 相似文献
89.
Nag K Fritzen-Garcia M Devraj R Panda AK 《Langmuir : the ACS journal of surfaces and colloids》2007,23(8):4421-4431
Pulmonary surfactants stabilize the lung by way of reducing surface tension at the air-lung interface of the alveolus. 31P NMR, thin-layer chromatography, and electrospray ionization mass spectroscopy of bovine lipid extract surfactant (BLES) confirmed dipalmitoylphosphatidylcholine (DPPC) to be the major phospholipid species, with significant amounts of palmitoyl-oleoylphosphatidylcholine, palmitoyl-myristoylphosphatidylcholine, and palmitoyl-oleoylphosphatidylglycerol. BLES and DPPC spread at the air-water interface were studied through surface pressure area, fluorescence, and Brewster angle microscopy measurements. Langmuir-Blodgett films of monomolecular films, deposited on mica, were characterized by atomic force microscopy. BLES films displayed shape, size, and vertical height profiles distinct from those of DPPC alone. Calcium ions in the subphase altered BLES film domain structure. The addition of cholesterol (4 mol %) resulted in the destabilization of compressed BLES films at higher surface pressures (>40 mN m-1) and the formation of multilayered structures, apparently consisting of stacked monolayers. The studies suggested potential roles for individual surfactant lipid components in supramolecular arrangements, which could be the contributing factors in pulmonary surfactant to attain low surface tension at the air-water interface. 相似文献
90.
Tetsurō Nakamura 《Journal of solid state chemistry》1981,36(2):234-240
The standard entropy change ΔS° for the reduction of nonmagnetic, nonconducting oxides, , has been estimated as a function of m, n, and temperature T from motional entropies of oxygen molecules and vibrational entropies of solid phases. An available formula of ΔS°calc = a · m + b · n with constant a and b based on effective Debye temperatures, θM = 165 K for M and θOX = 540 K for MmOn, agrees well with the observed ΔS°obs for M2O, MO, M2O3, MO2, M2O5, and MO3 in the temperature range T = 300 – 1300 K. Possible electronic entropy corrections are applied to ΔS°calc for M2O7 and MO4. 相似文献