全文获取类型
收费全文 | 208篇 |
免费 | 36篇 |
国内免费 | 4篇 |
专业分类
化学 | 27篇 |
晶体学 | 5篇 |
力学 | 60篇 |
数学 | 17篇 |
物理学 | 139篇 |
出版年
2023年 | 5篇 |
2022年 | 13篇 |
2021年 | 20篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 11篇 |
2013年 | 17篇 |
2012年 | 10篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 11篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有248条查询结果,搜索用时 31 毫秒
181.
Nanobubbles (NBs) have recently garnered widespread attention for their potential use as dual diagnostic and therapeutic agents. Similar to their micron-sized relatives (microbubbles), NBs are shell-stabilized, gas-cored bubbles that in conjunction with ultrasound can be used to increase imaging contrast, as well as provide a mechanism for trigger drug release and increased therapeutic delivery.In this review, we specifically focus on their development as agents to enhance drug delivery, discussing theory, characterization techniques, key formulations and prospects for translation into clinical use. 相似文献
182.
Hyväluoma J Koponen A Raiskinmäki P Timonen J 《The European physical journal. E, Soft matter》2007,23(3):289-293
The behaviour of liquid droplets on inclined heterogeneous surfaces was simulated by the lattice-Boltzmann method using the
Shan-Chen multiphase model. The effect of topography of the surface on the contact angle hysteresis was investigated. It is
shown in particular, by using anisotropic rough surfaces, how surface topography and thereby the continuity of the three-phase
contact line, affect this hysteresis. Our results clearly indicate that the superhydrophobicity of a surface cannot be judged
by the contact angle alone. 相似文献
183.
Adem Kaya 《高等学校计算数学学报(英文版)》2023,16(1):26-57
An adapted-bubbles approach which is a modification of the residual-free bubbles (RFB) method, is proposed for the Helmholtz problem in 2D. A new
two-level finite element method is introduced for the approximations of the bubble functions. Unlike the other equations such as the advection-diffusion equation,
RFB method when applied to the Helmholtz equation, does not depend on another
stabilized method to obtain approximations to the solutions of the sub-problems.
Adapted-bubbles (AB) are obtained by a simple modification of the sub-problems.
This modification increases the accuracy of the numerical solution impressively. We
provide numerical experiments with the AB method up to $ch = 5$ where $c$ is the
wavenumber and $h$ is the mesh size. Numerical tests show that the AB method is
better by far than higher order methods available in the literature. 相似文献
184.
A new system of dynamical equations was obtained by using the perturbation and potential flow theory to couple the pulsation and surface deformation of the second-order Legendre polynomials (P2) of three bubbles in a line. The feasibility and effectiveness of the model were verified by simulating the radial oscillations, surface deformation with P2, and shape evolution of three bubbles. The spherical radial pulsation and surface deformation of the three bubbles exhibit periodic behavior. The maximum secondary Bjerknes forces (SBFs) on the three bubbles are found not to depend on the system’s resonance frequency. Within a stable region, the SBFs of the three bubbles increase with increasing sound pressure amplitude but decrease with increasing distance between the bubbles. The primary Bjerknes force (PBF) on a bubble is significantly higher than the SBF on it. 相似文献
185.
We report a study of liquid jets which are formed by bubble collapse under cavitation-generated pressure waves. The results obtained for jets formed from samples of a multigrade motor oil provide the first evidence that such jets experience a significant degree of extensional deformation, at high rates of extension. The results support the conclusion that the reduced velocity and final length of such jets, relative to their Newtonian counterparts, is due to an increased resistance to extensional flow. Insofar as the multigrade oils studied here are made viscoelastic by polymer additives and evidently possess significant levels of resistance to extension, the results provide evidence in support of a mitigating effect of viscoelasticity on a cavitation damage mechanism, as mooted by Berker et al. (J Non Newton Fluid Mech 56:333, 1995). 相似文献
186.
Enhancement of shock waves in a porous medium saturated with a liquid containing soluble-gas bubbles 总被引:5,自引:0,他引:5
Evolution of a moderate-intensity shock wave and its enhancement after reflection from a rigid surface embedded in a porous medium are studied experimentally. The medium is saturated with a liquid that has bubbles of a soluble gas. A physical mechanism of shock wave enhancement in a saturated porous medium is proposed. Experimental data on the amplitude and velocity of reflected waves are compared with results of theoretical modeling. The process of gas bubble dissolution behind a shock wave is studied. 相似文献
187.
T. Kamppeter S.A. Leonel F.G. Mertens M.E. Gouvêa A.S.T. Pires A.S. Kovalev 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,21(1):93-102
The properties of dynamical solitons (magnon droplets) in the classical, two-dimensional anisotropic Heisenberg model with
easy-axis exchange anisotropy are studied. The solution of the Landau-Lifshitz equation in the continuum limit for the soliton
with topological charge q = 1 is obtained numerically using a shooting method. We analized a wide range of the anisotropy parameter and our results
are in good agreement with results obtained from spin dynamics simulations. The dependence of an internal precession frequency
of the soliton on both the anisotropy parameter and the radius of the soliton is also investigated. Finally, the limits of
applicability of the continuum approach are discussed.
Received 22 August 2000 相似文献
188.
The process of soap-bubble collapse is studied using a high-speed videocamera. Nine successive photographs of a collapsing bubble obtained in one experiment are presented. The final stages of collapse are analyzed using the model proposed, which allows for an analytical solution. Quantitative agreement between the experimental and theoretical results is achieved. 相似文献
189.
资产价格泡沫等市场异常现象使得有效市场假说理论受到质疑,研究者们更多的是从行为金融学的角度对这些现象进行解释,认为是由市场投资者的非理性因素所造成的。本文考虑了市场中投资者决策的异质性,构建了含有长期基础投资者和短期技术投资者的异质交易模型,以说明在投资者均具有理性预期的条件下,有效市场假说理论同样可以解释泡沫的产生。具体而言,技术投资者的交易行为使价格产生波动,基础投资者的存在则对波动起到放大作用,并会进一步导致泡沫的出现,随着基础投资者所占的比例增大,泡沫膨胀的速度加快,由此导致市场的波动越剧烈。研究结果为市场监管者提供了有益的启示:与其设置壁垒限制技术投资者的加入及交易活动,不如让越来越多的技术投资者加入到市场中来,这样更有益于市场的稳定。 相似文献
190.
B. G. Yemets 《International Journal of Infrared and Millimeter Waves》2000,21(5):787-791
We discuss an experimental evidence for a decrease in the volume of air dissolved in water caused by millimeter electromagnetic waves of low intensity. The changes obtained were much greater than the expected conditioned by a pure thermal effect. The result observed is explained by air bubbles that take an active part in a mechanism of withdrawing dissolved air from water. The variation of restoring the dissolved air volume up to an equilibrium level after ceasing irradiation of water by millimeter waves was investigated as well. 相似文献