全文获取类型
收费全文 | 8254篇 |
免费 | 739篇 |
国内免费 | 944篇 |
专业分类
化学 | 383篇 |
晶体学 | 14篇 |
力学 | 324篇 |
综合类 | 163篇 |
数学 | 7575篇 |
物理学 | 1478篇 |
出版年
2024年 | 15篇 |
2023年 | 95篇 |
2022年 | 103篇 |
2021年 | 157篇 |
2020年 | 185篇 |
2019年 | 226篇 |
2018年 | 261篇 |
2017年 | 280篇 |
2016年 | 254篇 |
2015年 | 202篇 |
2014年 | 300篇 |
2013年 | 1170篇 |
2012年 | 306篇 |
2011年 | 395篇 |
2010年 | 347篇 |
2009年 | 426篇 |
2008年 | 546篇 |
2007年 | 537篇 |
2006年 | 454篇 |
2005年 | 421篇 |
2004年 | 405篇 |
2003年 | 389篇 |
2002年 | 393篇 |
2001年 | 329篇 |
2000年 | 307篇 |
1999年 | 253篇 |
1998年 | 217篇 |
1997年 | 227篇 |
1996年 | 160篇 |
1995年 | 91篇 |
1994年 | 68篇 |
1993年 | 51篇 |
1992年 | 43篇 |
1991年 | 42篇 |
1990年 | 31篇 |
1989年 | 25篇 |
1988年 | 28篇 |
1987年 | 22篇 |
1986年 | 18篇 |
1985年 | 22篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1982年 | 16篇 |
1981年 | 9篇 |
1980年 | 12篇 |
1979年 | 11篇 |
1978年 | 13篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1936年 | 7篇 |
排序方式: 共有9937条查询结果,搜索用时 93 毫秒
981.
A Cameron-Martin-type theorem is proved for the canonical Brownian motion on the group of homeomorphisms of the circle. 相似文献
982.
983.
A weakly damped wave equation in the three‐dimensional (3‐D) space with a damping coefficient depending on the displacement is studied. This equation is shown to generate a dissipative semigroup in the energy phase space, which possesses finite‐dimensional global and exponential attractors in a slightly weaker topology. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
984.
To a semisimple and cosemisimple Hopf algebra over an algebraically closed field, we associate a planar algebra defined by
generators and relations and show that it is a connected, irreducible, spherical, non-degenerate planar algebra with non-zero
modulus and of depth two. This association is shown to yield a bijection between (the isomorphism classes, on both sides,
of) such objects. 相似文献
985.
本文研究了一类推广的控制收敛定理及其应用,利用对控制函数满足条件的修改,建立了推广的控制收敛定理,获得其在弱奇异性积分算子中的应用,简化了经典结论的证明. 相似文献
986.
In this paper, the dynamics of a generalized two-neuron model with self-connections and distributed delays are investigated, together with the stability of the equilibrium. In particular, the conditions under which the Hopf bifurcation occurs at the equilibrium are obtained for the weak kernel. This means that a family of periodic solutions bifurcates from the equilibrium when the bifurcation parameter exceeds a critical value. Explicit algorithms for determining the stability of the bifurcating periodic solutions and the direction of the Hopf bifurcation are derived by using the theory of normal form and center manifold [20]. Some numerical simulations are given to illustrate the effectiveness of the results found. The obtained results are new and they complement previously known results.This work was supported by the National Natural Science Foundation of China under Grants 60574043 and 60373067, the Natural Science Foundation of Jiangsu Province, China under Grants BK2003053. 相似文献
987.
988.
Lin ZHU Xiu Hong FENG Yan Lin YU 《数学学报(英文版)》2007,23(9):1629-1638
In this paper, we give identifications of bispinor space with Grassmann algebra, and with Clifford algebra. The multiplication in Clifford algebra provides an action on them. Lastly we have researched on the geometry of bispinor space, and define Dirac operators to get a Pythagoras equality. 相似文献
989.
E. Horozov 《Bulletin des Sciences Mathématiques》2002,126(7):605-614
In this paper we give another characterization of the strictly nilpotent elements in the Weyl algebra, which (apart from the polynomials) turn out to be all bispectral operators with polynomial coefficients. This also allows to reformulate in terms of bispectral operators the famous conjecture, that all the endomorphisms of the Weyl algebra are automorphisms (Dixmier, Kirillov, etc). 相似文献
990.
δlm is the parameter space of quadratic system (I)n=0. A partition of parameters corresponding to the existence and nonexistence of the limit cycle of the system is given in detail. The Hopf bifurcation surfaces of (I)m=0 are obtained, and the sketch of Hopf bifurcation surfaces of (I)n=0 are drawn. 相似文献