全文获取类型
收费全文 | 6938篇 |
免费 | 759篇 |
国内免费 | 678篇 |
专业分类
化学 | 3404篇 |
晶体学 | 42篇 |
力学 | 192篇 |
综合类 | 31篇 |
数学 | 3696篇 |
物理学 | 1010篇 |
出版年
2024年 | 22篇 |
2023年 | 90篇 |
2022年 | 135篇 |
2021年 | 272篇 |
2020年 | 422篇 |
2019年 | 377篇 |
2018年 | 373篇 |
2017年 | 169篇 |
2016年 | 270篇 |
2015年 | 278篇 |
2014年 | 418篇 |
2013年 | 456篇 |
2012年 | 343篇 |
2011年 | 541篇 |
2010年 | 413篇 |
2009年 | 529篇 |
2008年 | 536篇 |
2007年 | 563篇 |
2006年 | 458篇 |
2005年 | 274篇 |
2004年 | 230篇 |
2003年 | 239篇 |
2002年 | 145篇 |
2001年 | 88篇 |
2000年 | 87篇 |
1999年 | 82篇 |
1998年 | 78篇 |
1997年 | 51篇 |
1996年 | 57篇 |
1995年 | 46篇 |
1994年 | 61篇 |
1993年 | 48篇 |
1992年 | 41篇 |
1991年 | 22篇 |
1990年 | 17篇 |
1989年 | 16篇 |
1988年 | 21篇 |
1987年 | 19篇 |
1986年 | 13篇 |
1985年 | 20篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有8375条查询结果,搜索用时 109 毫秒
991.
992.
We develop the rough path counterpart of Itô stochastic integration and differential equations driven by general semimartingales. This significantly enlarges the classes of (Itô/forward) stochastic differential equations treatable with pathwise methods. A number of applications are discussed. 相似文献
993.
Takahiro Hashira Sachiko Ishida Tomomi Yokota 《Journal of Differential Equations》2018,264(10):6459-6485
This paper deals with the quasilinear degenerate Keller–Segel systems of parabolic–parabolic type in a ball of (). In the case of non-degenerate diffusion, Cie?lak–Stinner [3], [4] proved that if , where m denotes the intensity of diffusion and q denotes the nonlinearity, then there exist initial data such that the corresponding solution blows up in finite time. As to the case of degenerate diffusion, it is known that a solution blows up if (see Ishida–Yokota [13]); however, whether the blow-up time is finite or infinite has been unknown. This paper gives an answer to the unsolved problem. Indeed, the finite-time blow-up of energy solutions is established when . 相似文献
994.
For Toeplitz operators acting on the weighted Fock space , we consider the semi-commutator , where is a certain weight parameter that may be interpreted as Planck's constant ? in Rieffel's deformation quantization. In particular, we are interested in the semi-classical limit
()
It is well-known that tends to 0 under certain smoothness assumptions imposed on f and g. This result was recently extended to by Bauer and Coburn. We now further generalize (?) to (not necessarily bounded) uniformly continuous functions and symbols in the algebra of bounded functions having vanishing mean oscillation on . Our approach is based on the algebraic identity , where denotes the Hankel operator corresponding to the symbol g, and norm estimates in terms of the (weighted) heat transform. As a consequence, only f (or likewise only g) has to be contained in one of the above classes for (?) to vanish. For g we only have to impose , e.g. . We prove that the set of all symbols with the property that for all coincides with . Additionally, we show that holds for all . Finally, we present new examples, including bounded smooth functions, where (?) does not vanish. 相似文献
995.
We derive trace formulas for a pair of self-adjoint operators and H under the assumption that is in a Schatten class. This extends the trace formulas of [8], where V alone is assumed to be in a Schatten class. Our trace formulas apply, in particular, in the setting of differential operators and are based on Taylor-like approximations of operator functions. This significantly improves non-Taylor based trace formulas of [10]. 相似文献
996.
Javad Mashreghi Julian Ransford Thomas Ransford 《Journal of Functional Analysis》2018,274(11):3254-3262
We show that every linear functional on the Dirichlet space that is non-zero on nowhere-vanishing functions is necessarily a multiple of a point evaluation. Continuity of the functional is not assumed. As an application, we obtain a characterization of weighted composition operators on the Dirichlet space as being exactly those linear maps that send nowhere-vanishing functions to nowhere-vanishing functions.We also investigate possible extensions to weighted Dirichlet spaces with superharmonic weights. As part of our investigation, we are led to determine which of these spaces contain functions that map the unit disk onto the whole complex plane. 相似文献
997.
998.
Jaiung Jun 《Journal of Pure and Applied Algebra》2018,222(8):2063-2088
We develop notions of valuations on a semiring, with a view toward extending the classical theory of abstract nonsingular curves and discrete valuation rings to this general algebraic setting; the novelty of our approach lies in the implementation of hyperrings to yield a new definition (hyperfield valuation). In particular, we classify valuations on the semifield (the max-plus semifield of rational numbers) and also valuations on the ‘function field’ (the semifield of rational functions over ) which are trivial on . We construct and study the abstract curve associated to in relation to the projective line over the field with one element and the tropical projective line. Finally, we discuss possible connections to tropical curves and Berkovich's theory of analytic spaces. 相似文献
999.
Leovigildo Alonso Tarrío Ana Jeremías López Marta Pérez Rodríguez María J. Vale Gonsalves 《Journal of Pure and Applied Algebra》2018,222(4):828-845
Let be an Adams geometric stack. We show that , its derived category of quasi-coherent sheaves, satisfies the axioms of a stable homotopy category defined by Hovey, Palmieri and Strickland in [13]. Moreover we show how this structure relates to the derived category of comodules over a Hopf algebroid that determines . 相似文献
1000.
A non-nilpotent variety of algebras is almost nilpotent if any proper subvariety is nilpotent. Let the base field be of characteristic zero. It has been shown that for associative or Lie algebras only one such variety exists. Here we present infinite families of such varieties. More precisely we shall prove the existence of1) a countable family of almost nilpotent varieties of at most linear growth and2) an uncountable family of almost nilpotent varieties of at most quadratic growth. 相似文献