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981.
B. Mukeru 《中国物理C(英文版)》2023,47(2):024104-024104-5
An analysis of the breakup of the \begin{document}$ ^{31}{\rm Ne} $\end{document} ![]()
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weakly-bound neutron-halo system on a lead target is presented, considering the \begin{document}$ 2p_{3/2} $\end{document} ![]()
![]()
and \begin{document}$ 1f_{7/2} $\end{document} ![]()
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ground-state configurations. It is shown that a high centrifugal barrier almost wipes out the breakup channel, thus assimilating the breakup of a weakly-bound system to that of a tightly-bound system, and also reduces the range of the monopole nuclear potential. Consequently, a high centrifugal barrier prevents the suppression of the Coulomb-nuclear interference (CNI) peak by weakening couplings to the breakup channel and reducing the range of the monopole nuclear potential, two main factors that would otherwise suppress such a peak. The present study also identifies couplings to the breakup channel and a long-ranged monopole nuclear potential as the main factors that lead to the suppression of the CNI peak. A low centrifugal barrier together with a Coulomb barrier would also effectively prevent the suppression of the CNI peak in proton-halos as reported in the case of the \begin{document}$ ^8{\rm B} $\end{document} ![]()
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proton-halo. 相似文献
982.
The dynamic flow behavior of polyamide-6 (PA-6) and a nanocomposite (PNC) based on it was studied. The latter resin contained
2 wt% of organoclay. The two materials were blended in proportions of 0, 25, 50, 75, and 100 wt% PNC. The dynamic shear rheological
properties of well-dried specimens were measured under N2 at T=240 °C, frequency ω=0.1–100 rad/s, and strains γ=10 and 40%. At constant T, γ, and ω the time sweeps resulted in significant
increases of the shear moduli. The γ and ω scans showed a complex rheological behavior of all clay-containing specimens. At
γ=10% the linear viscoelasticity was observed for all compositions only at ω>1 rad/s, while at γ=40% only for 0 and 25 wt%
of PNC. However, the effect was moderate, namely decreasing G′ and G′′ (at ω=6.28 rad/s; γ=50%) by 15 and 7.5%, respectively.
For compositions containing >25 wt% PNC two types of non-linearity were detected. At ω≤ωc=1.4 ± 0.2 rad/s yield stress provided evidence of a 3-D structure. At ω > ωc, G′ and G′′ were sensitive to shear history – the effect was reversible. From the frequency scans at ω > ωc the zero-shear relative viscosity vs concentration plot was constructed. The initial slope gave the intrinsic viscosity from
which the aspect ratio of organoclay particles, p=287 ± 9 was calculated, in agreement with the value calculated from the
reduced permeability data, p=286.
Received: 24 May 2001 Accepted: 27 August 2001 相似文献
983.
A lattice boltzmann model for compressible perfect gas 总被引:1,自引:0,他引:1
A new lattice Boltzmann model for compressible perfect gas is proposed. The numerical example shows that it can be used to
simulate shock wave and contact discontinuity. The results are comparable with those obtained by traditional methods. The
ratio of specific heats γ may be chosen according to the requirement of problems.
The project supported by the National Natural Science Foundation of China 相似文献
984.
通过对高性能 (AS系列 )固化剂与水泥的对比试验 ,研究其在天津软弱地基加固中适用性和优越性 ,并得出一套实用的固化剂加固软土地基的施工设计参数 相似文献
985.
Wei Tong 《International Journal of Heat and Fluid Flow》1999,20(6):457-633
The effect of the aspect ratio on natural convection in water subjected to density inversion has been investigated in this study. Numerical simulations of the two-dimensional, steady state, incompressible flow in a rectangular enclosure with a variety of aspect ratios, ranging from 0.125 to 100, have been accomplished using a finite element model. Computations cover Rayleigh numbers from 103 to 106. Results reveal that the aspect ratio, A, the Rayleigh number, Ra, and the density distribution parameter, R, are the key parameters to determine the heat transfer and fluid flow characteristics for density inversion fluids in an enclosure. A new correlation for predicting the maximum mean Nusselt number is proposed in the form of
, with the constants a and b depending on density distribution number R. It is demonstrated that the aspect ratio has a strong impact on flow patterns and temperature distributions in rectangular enclosures. The stream function ratio Ψinv/|Ψreg| is introduced to describe quantitatively the interaction between inversional and regular convection. For R=0.33, the density inversion enhancement is observed in the regime near A=3. 相似文献
986.
Fibrous thermal insulations are widely used to conserve energy in ambient to high temperature applications including buildings, solar collectors, heat exchangers, furnaces and thermal protection systems of reusable launch vehicles. It has long been recognised that zirconia has the lowest thermal conductivity of commercial refractories. The thermal conductivity of a zirconia fibrous medium is strongly dependent of its bulk density; high bulk densities of zirconia fibers provide the most effective insulation at high temperatures. Lee's theory for radiative transfer through fibrous media is used in this paper. The two-flux model is applied to determine the backward and forward parameters of a medium of zirconia fibers oriented in parallel planes. Theoretical calculations of the backscatter factor and absorption ratio of this medium are carried out in the visible spectrum for different size parameters of the fibers and for three different temperatures. Our results show that the backscatter factor of zirconia fibrous insulations is maximum, and therefore the heat transfer by the fibrous medium is the lowest, for a size parameter of 0.45 for all the temperatures studied. We also observed that the backscatter factor decreases with increasing temperature. 相似文献
987.
讨论了空沿敏感韧性及超塑性材料由于变形损伤引起的体积膨胀,提出了弹塑性有限变形下表征体积膨胀特性的横向主形系数在各向同性损伤条件下的解析表达式。 相似文献
988.
A one-dimensional approximate analytical model, which preserves the main features of soil-crop-atmospheric hydrodynamics,
has been suggested for plant roots of low soil-root conductivity ratio (SRCR). The proposed approach involves physically based
concepts, such as mass balance equation, Darcy’s law, and related water uptake and plant transpiration functions. Two main
assumptions have been made to derive the analytical solution: (1) gravitational flow is adopted and (2) the uniform soil moisture
distribution within the root water activity zone is supposed. The mass balance equation in its integral form is solved by
the method of characteristics. This leads to the two functional equations for soil pressure head and root potential, which
can be solved simultaneously by using common software. The model has been further verified against the numerical one. The
model represents a reasonable compromise between the complicated mechanism of unsaturated water flow with root water uptake
(RWU) and still insufficient knowledge of the soil-plant-atmospheric continuum. It is able to account for temporal fluctuations
in root activity zone and provides a relatively simple algorithm for investigation of RWU-mechanism. Besides the theoretical
and applicative importance, this flow model yields water and velocity distributions within soil profile, and, thereby, constitutes
a preliminary step toward solution of contaminant transport problems in vadose zone.
Deceased 相似文献
989.
990.
Here, the large amplitude free flexural vibration behaviors of thin laminated composite skew plates are investigated using finite element approach. The formulation includes the effects of shear deformation, in-plane and rotary inertia. The geometric non-linearity based on von Karman's assumptions is introduced. The non-linear governing equations obtained employing Lagrange's equations of motion are solved using the direct iteration technique. The variation of non-linear frequency ratios with amplitudes is brought out considering different parameters such as skew angle, number of layers, fiber orientation, boundary condition and aspect ratio. The influence of higher vibration modes on the non-linear dynamic behavior of laminated skew plates is also highlighted. The present study reveals the redistribution of vibrating mode shape at certain amplitude of vibration depending on geometric and lamination parameters of the plate. Also, the degree of hardening behavior increases with the skew angle and its rate of change depends on the level of amplitude of vibration. 相似文献