全文获取类型
收费全文 | 6605篇 |
免费 | 581篇 |
国内免费 | 414篇 |
专业分类
化学 | 2384篇 |
晶体学 | 51篇 |
力学 | 2604篇 |
综合类 | 28篇 |
数学 | 917篇 |
物理学 | 1616篇 |
出版年
2024年 | 6篇 |
2023年 | 78篇 |
2022年 | 90篇 |
2021年 | 141篇 |
2020年 | 196篇 |
2019年 | 148篇 |
2018年 | 185篇 |
2017年 | 196篇 |
2016年 | 254篇 |
2015年 | 173篇 |
2014年 | 239篇 |
2013年 | 500篇 |
2012年 | 333篇 |
2011年 | 372篇 |
2010年 | 301篇 |
2009年 | 376篇 |
2008年 | 345篇 |
2007年 | 351篇 |
2006年 | 300篇 |
2005年 | 357篇 |
2004年 | 265篇 |
2003年 | 262篇 |
2002年 | 247篇 |
2001年 | 202篇 |
2000年 | 168篇 |
1999年 | 154篇 |
1998年 | 140篇 |
1997年 | 142篇 |
1996年 | 114篇 |
1995年 | 136篇 |
1994年 | 108篇 |
1993年 | 95篇 |
1992年 | 72篇 |
1991年 | 80篇 |
1990年 | 56篇 |
1989年 | 49篇 |
1988年 | 69篇 |
1987年 | 58篇 |
1986年 | 62篇 |
1985年 | 39篇 |
1984年 | 33篇 |
1983年 | 14篇 |
1982年 | 45篇 |
1981年 | 15篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1973年 | 3篇 |
1971年 | 4篇 |
1957年 | 2篇 |
排序方式: 共有7600条查询结果,搜索用时 15 毫秒
41.
42.
M. Dubé C. Daneault V. Vuorinen M. Alava M. Rost 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(1):15-26
We investigate the structure and dynamics of the interface between
two immiscible liquids in a three-dimensional disordered porous
medium. We apply a phase-field model that includes explicitly
disorder and discuss both spontaneous and forced imbibition.
The structure of the interface is dominated by a length scale
ξ× which arises from liquid conservation. We further show
that disorder in the capillary and permeability act on different
length scales and give rise to different scalings and
structures of the interface properties. We conclude with a
range of applications. 相似文献
43.
A. V. Kravtsov 《Computational Mathematics and Mathematical Physics》2007,47(11):1875-1884
A linear problem of parametric oscillations of a low-viscous two-layer fluid in a closed vessel partially filled with a porous medium is studied. An asymptotic solution is constructed on the basis of combined application of boundary functions and averaging methods. Approximate formulas for boundaries of instability domains in the case of subharmonic and harmonic resonances are derived. 相似文献
44.
Bianchi type-III magnetized cosmological model when the field of gravitation is governed by either a perfect fluid or cosmic
string is investigated in Rosen’s [1] bimetric theory of gravitation. To complete determinate solution, the condition, viz.,
A=(BC)
n
, where n is a constant, between the metric potentials is used. We have assumed different equations of state for cosmic string [2]
for the complete solution of the model. Some physical and geometrical properties of the exhibited model are discussed and
studied. 相似文献
45.
Jindun Liu A. J. B. Kemperman G. H. Koops M. Wessling 《中国颗粒学报》2006,4(2):98-102
A novel method of fabricating composite mosaic membranes was studied on the basis of interracial polymerization (IP) by coating a thin selective layer onto the surface of a micro-porous hollow-fiber membrane, in which, 2,5-diaminobenzene sulfonic acid was used as one monomer of the IP reaction, and a mixture of trimesoyl chloride (TMCI) and 4-(chloromethyl) benzoyl chloride as the other monomer. Through the IP reaction a thin selective layer with negatively charged groups could be first formed on the polyethersulfone (PES) support membrane. Then trimethylamine solution was introduced to modify the IP layer through a quaternization reaction. Thus the selective layer of this composite membrane contained both negatively charged and positively charged groups to perform the mosaic functionality. Characterization of the composite mosaic membranes was carried out through permeation experiments using different inorganic salts and dyes. The experimental results showed that the membranes could permeate both mono- and bi-valent inorganic salts, but reject larger organic molecules. Such a mosaic membrane is potentially useful for the separation of salts from water-soluble organics, especially in dye and textile industries. 相似文献
46.
带有无限到达源的Re-entrant Line的稳定性 总被引:1,自引:0,他引:1
用Foster判别准则,Weiss[13]给出了带有无限到达源的两站三步re-entrant line的稳定性的充分条件.本文用两种不同的方法得到了其稳定性的充分必要条件,即: 二维随机游动方法和Foster判别准则.同时,我们又用流体模型方法得到了系统稳定的充分条件,大大地简化了Weiss[13]的证明. 相似文献
47.
A new probabilistic cellular automaton model is introduced to simulate cluster and interface growth in two dimensions. The dynamics of this model is an extension to higher dimensions of the compact directed percolation studied by Essam. Numerical results indicate that the two-dimensional cluster coarsening and growth can be described only approximately by the conventional cluster size scaling due to a crossover in the growth mode. The spreading of the initially flat interface follows a purely diffusional,t
1/2, law. 相似文献
48.
Recent experiments revealed that the dielectric dispersion spectrum of fission yeast cells in a suspension was mainly composed of two sub-dispersions. The low-frequency sub-dispersion depended on the cell length, while the high-frequency one was independent of it. The cell shape effect was simulated by an ellipsoidal cell model but the comparison between theory and experiment was far from being satisfactory. Prompted by the discrepancy, we proposed the use of spectral representation to analyze more realistic cell models. We adopted a shell-spheroidal model to analyze the effects of the cell membrane. It is found that the dielectric property of the cell membrane has only a minor effect on the dispersion magnitude ratio and the characteristic frequency ratio. We further included the effect of rotation of dipole induced by an external electric field, and solved the dipole-rotation spheroidal model in the spectral representation.Good agreement between theory and experiment has been obtained. 相似文献
49.
泊松类型方程边界元解法 总被引:2,自引:0,他引:2
本文采用高阶拉普拉斯算子基本解将泊松类型方程的区域积分全部变换成边界积分,使计算问题的维数减少一维.通过斯托克斯方程的算例,表明本文所用的方法是有效的方法。 相似文献
50.