全文获取类型
收费全文 | 3497篇 |
免费 | 317篇 |
国内免费 | 314篇 |
专业分类
化学 | 864篇 |
晶体学 | 5篇 |
力学 | 507篇 |
综合类 | 46篇 |
数学 | 1478篇 |
物理学 | 1228篇 |
出版年
2024年 | 7篇 |
2023年 | 39篇 |
2022年 | 53篇 |
2021年 | 79篇 |
2020年 | 98篇 |
2019年 | 90篇 |
2018年 | 73篇 |
2017年 | 74篇 |
2016年 | 108篇 |
2015年 | 87篇 |
2014年 | 135篇 |
2013年 | 297篇 |
2012年 | 164篇 |
2011年 | 248篇 |
2010年 | 169篇 |
2009年 | 213篇 |
2008年 | 206篇 |
2007年 | 229篇 |
2006年 | 198篇 |
2005年 | 169篇 |
2004年 | 169篇 |
2003年 | 148篇 |
2002年 | 134篇 |
2001年 | 123篇 |
2000年 | 117篇 |
1999年 | 91篇 |
1998年 | 78篇 |
1997年 | 73篇 |
1996年 | 63篇 |
1995年 | 41篇 |
1994年 | 44篇 |
1993年 | 32篇 |
1992年 | 36篇 |
1991年 | 41篇 |
1990年 | 19篇 |
1989年 | 24篇 |
1988年 | 19篇 |
1987年 | 16篇 |
1986年 | 16篇 |
1985年 | 10篇 |
1984年 | 18篇 |
1983年 | 9篇 |
1982年 | 16篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 9篇 |
1976年 | 5篇 |
1973年 | 4篇 |
排序方式: 共有4128条查询结果,搜索用时 15 毫秒
141.
It is known that one-dimensional lattice problems with a discrete, finite set of states per site generically have periodic ground states (GSs). We consider slightly less generic cases, in which the Hamiltonian is constrained by either spin (S) or spatial (I) inversion symmetry (or both). We show that such constraints give rise to the possibility ofdisordered GSs over a finite fraction of the coupling-parameter space—that is, without invoking any nongeneric fine tuning of coupling constants, beyond that arising from symmetry. We find that such disordered GSs can arise for many values of the number of statesk at each site and the ranger of the interaction. The Ising (k=2) case is the least prone to disorder:I symmetry allows for disordered GSs (without fine tuning) only forr5, whileS symmetry never gives rise to disordered GSs. 相似文献
142.
In the present paper, blood flow through a tapered artery with a stenosis is analyzed, assuming the flow is steady and blood is treated as non-Newtonian power law fluid model. Exact solution has been evaluated for velocity, resistance impedance, wall shear stress and shearing stress at the stenosis throat. The graphical results of different types of tapered arteries (i.e. converging tapering, diverging tapering, non-tapered artery) have been examined for different parameters of interest. Some special cases of the problem are also presented. 相似文献
143.
This paper studies decoupled numerical methods for a mixed Stokes/Darcy model for coupling fluid and porous media flows. A two-level algorithm is proposed and analyzed in Mu and Xu (2007) [10]. We generalize the two-level algorithm to a multilevel algorithm in this paper and present numerical analysis on the error estimates for the multilevel algorithm. The multilevel algorithm solves the mixed Stokes/Darcy system by applying efficient legacy code for single model solvers to solve two decoupled Stokes and Darcy subproblems on all the subsequently refined meshes, except for a much smaller global problem only on a very coarse initial mesh. Numerical experiments are conducted for both the two-level and multilevel algorithms to illustrate their effectiveness and efficiency, and validate the related theoretical analysis. 相似文献
144.
《Physics letters. A》2020,384(26):126642
A novel method to make Lagrangians Galilean invariant is developed. The method, based on null Lagrangians and their gauge functions, is used to demonstrate the Galilean invariance of the Lagrangian for Newton's law of inertia. It is suggested that this new solution of an old physics problem may have implications and potential applications to all gauge-based theories of physics. 相似文献
145.
《Discrete Mathematics》2022,345(5):112802
We study logical limit laws for uniform attachment random graphs. In this random graph model, vertices and edges are introduced recursively: at time , the vertex is introduced together with m edges joining the new vertex with m different vertices chosen uniformly at random from . We prove that this random graph obeys convergence law for first-order sentences with at most variables. 相似文献
146.
The effects of plasma functionalized water (PFW) and its combination with ultrasound (UPFW) on the functional and bioactive properties of small yellow croaker protein hydrolysates (SYPHs) produced from three enzymes were investigated. Fluorescence and UV–Vis spectroscopy indicated that SYPHs tended to unfold with increasing intensity and shift in wavelengths to more flexible conformations under PFW and UPFW treatments. Particle size distribution and microstructure analysis revealed that treatments could disrupt aggregation of protein molecules to increase the roughness, specific surface area, and decrease the particle size of peptides during hydrolysis. The partially denatured structure of SYPHs induced by treatments increased the susceptibility of the fish proteins to exogenous enzymes, thereby accelerating the hydrolytic process to yield peptides with improved solubility, decreased emulsifying and foaming properties, and improved enzyme-specific antioxidant properties. The results revealed that the functionality of SYPHs was influenced by the treatment method and the enzyme type employed. 相似文献
147.
A PICARD TYPE THEOREM AND BLOCH LAW 总被引:9,自引:0,他引:9
Ye Yasheng 《数学年刊B辑(英文版)》1994,15(1):75-80
A PICARD TYPE THEOREM AND BLOCH LAW ¥YEYASHENGAbstract:Apicardtypetheoremisproved,andacounterexampleisgiventoshowthattheBolch... 相似文献
148.
Vladimir Dobrić 《Journal of Theoretical Probability》1994,7(1):129-134
IfB is a weakly compactly generated Banach space andf: (S,S, ) satisfies the strong law of large numbers, thenf=f
1+f
2, wheref
1 is Bochner -integrable andf
2 is Pettis -integrable with Pettis norm 0. The decomposition is unique. 相似文献
149.
Samia Beghdadi-Sakrani 《Journal of Theoretical Probability》2003,16(4):789-812
We consider the stochastic differential equation: dX
t
=(|X
t
|)dB
t
, where B is a Brownian motion and is a non-Hölder Borel function. A sufficient condition of pathwise uniqueness is given. 相似文献
150.
提出普遍定律和非普遍定律以及“协变”与“可导出”的明确定义,证明狭义相对性原理(及其伽利略近似)要求在惯性系变换下,自然界普遍定律是协变的,非普遍定律不协变但是“可导出”的,一切定律都服从相对性原理,从而进一步解答了由爱因斯坦,朗道关于狭义相对性原理的一种错误表述所引起的“协变性疑难”,还将有关结论推广到广义相对性原理情况。 相似文献