全文获取类型
收费全文 | 6307篇 |
免费 | 360篇 |
国内免费 | 235篇 |
专业分类
化学 | 600篇 |
晶体学 | 9篇 |
力学 | 935篇 |
综合类 | 46篇 |
数学 | 2854篇 |
物理学 | 2458篇 |
出版年
2024年 | 4篇 |
2023年 | 86篇 |
2022年 | 134篇 |
2021年 | 169篇 |
2020年 | 182篇 |
2019年 | 196篇 |
2018年 | 193篇 |
2017年 | 190篇 |
2016年 | 211篇 |
2015年 | 188篇 |
2014年 | 316篇 |
2013年 | 470篇 |
2012年 | 332篇 |
2011年 | 376篇 |
2010年 | 327篇 |
2009年 | 454篇 |
2008年 | 382篇 |
2007年 | 382篇 |
2006年 | 294篇 |
2005年 | 289篇 |
2004年 | 248篇 |
2003年 | 228篇 |
2002年 | 158篇 |
2001年 | 136篇 |
2000年 | 138篇 |
1999年 | 118篇 |
1998年 | 131篇 |
1997年 | 93篇 |
1996年 | 79篇 |
1995年 | 55篇 |
1994年 | 74篇 |
1993年 | 48篇 |
1992年 | 49篇 |
1991年 | 51篇 |
1990年 | 23篇 |
1989年 | 22篇 |
1988年 | 7篇 |
1987年 | 16篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 4篇 |
1957年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有6902条查询结果,搜索用时 31 毫秒
1.
《Journal of Pure and Applied Algebra》2022,226(8):107024
We solve a combinatorial question concerning eigenvalues of the universal intertwining endomorphism of a subset representation. 相似文献
2.
3.
The growth-fragmentation equation describes a system of growing and dividing particles, and arises in models of cell division, protein polymerisation and even telecommunications protocols. Several important questions about the equation concern the asymptotic behaviour of solutions at large times: at what rate do they converge to zero or infinity, and what does the asymptotic profile of the solutions look like? Does the rescaled solution converge to its asymptotic profile at an exponential speed? These questions have traditionally been studied using analytic techniques such as entropy methods or splitting of operators. In this work, we present a probabilistic approach: we use a Feynman–Kac formula to relate the solution of the growth-fragmentation equation to the semigroup of a Markov process, and characterise the rate of decay or growth in terms of this process. We then identify the Malthus exponent and the asymptotic profile in terms of a related Markov process, and give a spectral interpretation in terms of the growth-fragmentation operator and its dual. 相似文献
4.
Erosion and sediments transport processes have a great impact on industrial structures and on water quality. Despite its limitations, the Saint‐Venant‐Exner system is still (and for sure for some years) widely used in industrial codes to model the bedload sediment transport. In practice, its numerical resolution is mostly handled by a splitting technique that allows a weak coupling between hydraulic and morphodynamic distinct softwares but may suffer from important stability issues. In recent works, many authors proposed alternative methods based on a strong coupling that cure this problem but are not so trivial to implement in an industrial context. In this work, we then pursue 2 objectives. First, we propose a very simple scheme based on an approximate Riemann solver, respecting the strong coupling framework, and we demonstrate its stability and accuracy through a number of numerical test cases. However, second, we reinterpret our scheme as a splitting technique and we extend the purpose to propose what should be the minimal coupling that ensures the stability of the global numerical process in industrial codes, at least, when dealing with collocated finite volume method. The resulting splitting method is, up to our knowledge, the only one for which stability properties are fully demonstrated. 相似文献
5.
6.
The sunset diagram of λφ4 theory is evaluated numerically in cutoff scheme and a nonzero finite term(in accordance with dimensional regularization (DR) result) is found in contrast to published calculations. This findingdramatically reduces the critical couplings for symmetry breaking in the two-loop effective potential discussed in ourprevious work. 相似文献
7.
J.V.P. de OliveiraA.V. Cardona M.T. VilhenaR.C. Barros 《Journal of Quantitative Spectroscopy & Radiative Transfer》2002,73(1):55-62
We describe a semi-analytical numerical method for coherent isotropic scattering time-dependent radiative transfer problems in slab geometry. This numerical method is based on a combination of two classes of numerical methods: the spectral methods and the Laplace transform (LTSN) methods applied to the radiative transfer equation in the discrete ordinates (SN) formulation. The basic idea is to use the essence of the spectral methods and expand the intensity of radiation in a truncated series of Laguerre polynomials in the time variable and then solve recursively the resulting set of “time-independent” SN problems by using the LTSN method. We show some numerical experiments for a typical model problem. 相似文献
8.
一类非线性Schr(o)dinger方程的守恒差分法与Fourier谱方法 总被引:1,自引:0,他引:1
考察了一类带导数项的非线性Schrodinger方程的周期边值问题,提出了一种守恒的差分格式,在空间方向上采用Fourier谱方法,证明了格式的稳定性和收敛性.数值试验得到了与理论分析一致的结果. 相似文献
9.
Zhong-Qing Wang 《Journal of Mathematical Analysis and Applications》2002,274(1):374-403
An orthogonal system of rational functions is discussed. Some inverse inequalities, imbedding inequalities and approximation results are obtained. Two model problems are considered. The stabilities and convergences of proposed rational spectral schemes and rational pseudospectral schemes are proved. The techniques used in this paper are also applicable to other problems on the whole line. Numerical results show the efficiency of this approach. 相似文献
10.
Josep Maria Izquierdo 《TOP》2006,14(2):375-398
The paper introduces a refinement of the notion of population monotonic allocation scheme, called regular population monotonic
allocation scheme (regularpmas). This refinement is based on economic situations in which players may have to select new partners from a set of potential
players and in which there exist certain capacity constraints. A sufficient condition for the existence of a regularpmas is given. For the class of games with regularpmas, we prove that the core coincides with the Davis and Maschler and the Mas-Colell bargaining sets. 相似文献