全文获取类型
收费全文 | 5969篇 |
免费 | 750篇 |
国内免费 | 298篇 |
专业分类
化学 | 143篇 |
晶体学 | 2篇 |
力学 | 1007篇 |
综合类 | 75篇 |
数学 | 4877篇 |
物理学 | 913篇 |
出版年
2024年 | 18篇 |
2023年 | 80篇 |
2022年 | 89篇 |
2021年 | 123篇 |
2020年 | 155篇 |
2019年 | 141篇 |
2018年 | 141篇 |
2017年 | 165篇 |
2016年 | 158篇 |
2015年 | 131篇 |
2014年 | 280篇 |
2013年 | 591篇 |
2012年 | 257篇 |
2011年 | 335篇 |
2010年 | 334篇 |
2009年 | 414篇 |
2008年 | 421篇 |
2007年 | 401篇 |
2006年 | 323篇 |
2005年 | 290篇 |
2004年 | 245篇 |
2003年 | 226篇 |
2002年 | 231篇 |
2001年 | 180篇 |
2000年 | 174篇 |
1999年 | 167篇 |
1998年 | 169篇 |
1997年 | 118篇 |
1996年 | 104篇 |
1995年 | 78篇 |
1994年 | 79篇 |
1993年 | 64篇 |
1992年 | 56篇 |
1991年 | 49篇 |
1990年 | 49篇 |
1989年 | 18篇 |
1988年 | 19篇 |
1987年 | 25篇 |
1986年 | 18篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 17篇 |
1981年 | 14篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1957年 | 4篇 |
排序方式: 共有7017条查询结果,搜索用时 15 毫秒
81.
曼合布拜·热合木 《新疆大学学报(理工版)》2003,(1)
讨论了一类具有扩散率和 III类功能性反应的非自治捕食系统 ,证明了在适当条件下 ,系统是持久的 ,进一步如果系统是周期系统 ,则在一定条件下存在惟一全局稳定的周期解 . 相似文献
82.
Kazumi Tsukada 《Geometriae Dedicata》1997,68(1):61-71
We investigate holomorphic maps between compact generalized Hopf manifolds (i.e., locally conformal Kähler manifolds with parallel Lee form). We show that they preserve the canonical foliations. Moreover, we study compact complex submanifolds of g.H. manifolds and holomorphic submersions from compact g.H. manifolds. 相似文献
83.
滕志东 《数学物理学报(A辑)》1998,18(2):169-175
该文研究周期二维Lotka-Volterra捕食食饵系统解的有界性,持续生存性以及正周期解的存在性和全局稳定性.并将结果推广到食饵有补充的周期二维Lotka-Volterra竞争系统上去,得到了一系列新的结果,改进和推广了文[1—3]的主要结论. 相似文献
84.
Researchers first examined the problem of separable concave programming more than thirty years ago, making it one of the earliest branches of nonlinear programming to be explored. This paper proposes a new algorithm that finds the exact global minimum of this problem in a finite number of iterations. In addition to proving that our algorithm terminates finitely, the paper extends a guarantee of finiteness to all branch-and-bound algorithms for concave programming that (1) partition exhaustively using rectangular subdivisions and (2) branch on the incumbent solution when possible. The algorithm uses domain reduction techniques to accelerate convergence; it solves problems with as many as 100 nonlinear variables, 400 linear variables and 50 constraints in about five minutes on an IBM RS/6000 Power PC. An industrial application with 152 nonlinear variables, 593 linear variables, and 417 constraints is also solved in about ten minutes. 相似文献
85.
Masakazu Muramatsu 《Mathematical Programming》1998,83(1-3):393-406
In this paper, we introduce an affine scaling algorithm for semidefinite programming (SDP), and give an example of a semidefinite
program such that the affine scaling algorithm converges to a non-optimal point. Both our program and its dual have interior
feasible solutions and unique optimal solutions which satisfy strict complementarity, and they are non-degenerate everywhere. 相似文献
86.
Breathers in discrete nonlinear ferrimagnetic spin lattices are investigated for both easy-axis and easy-plane configurations.
The region in frequency space of the formation of breathers is determined and the anticontinuum limit discussed. The monochromatic
and the coloured breathers are found out numerically for different parameters and different conditions of excitations. 相似文献
87.
Hopf Modules and Noncommutative Differential Geometry 总被引:1,自引:0,他引:1
We define a new algebra of noncommutative differential forms for any Hopf algebra with an invertible antipode. We prove that there is a one-to-one correspondence between anti-Yetter–Drinfeld modules, which serve as coefficients for the Hopf cyclic (co)homology, and modules which admit a flat connection with respect to our differential calculus. Thus, we show that these coefficient modules can be regarded as “flat bundles” in the sense of Connes’ noncommutative differential geometry. 相似文献
88.
In this paper, we study the existence of periodic orbits bifurcating from stationary solutions of a planar dynamical system
of Filippov type. This phenomenon is interpreted as a generalized Hopf bifurcation. In the case of smoothness, Hopf bifurcation
is characterized by a pair of complex conjugate eigenvalues crossing through the imaginary axis. This method does not carry
over to nonsmooth systems, due to the lack of linearization at the origin which is located on the line of discontinuity. In
fact, generalized Hopf bifurcation is determined by interactions between the discontinuity of the system and the eigen-structures
of all subsystems. With the help of geometrical observations for a corresponding piecewise linear system, we derive an analytical
method to investigate the existence of periodic orbits that are
obtained by searching for the fixed points of return maps. 相似文献
89.
In1969,Sweedler[1]giventhedecompositiontheoreyofcoalgebraswhicharecocommu-tative.In1975,Kaplansky[2]showedthatanycoalgebracanbeuniquelydecomposedintoadirectsumofitsindecomposablesubcoalgebras.From1978to1992,Shudo[3]andXu[4]consructuredtheindecomposabledirectsumcomponentsofacoalggebra,viadefineequivalenceralationforthesetofsimplesubcoalgebras.Asweknow,themodolecoalgebraisthennaturalgeneralizationofcoalgebra.AndittakesplayanimportentroleintheDrinfelddouble.Inthispaper,wediscussthedecompositio… 相似文献
90.
Bai-sheng Wu 《计算数学(英文版)》1998,(5)
1.IntroductionThispaperisdevotedtothecalculatiollofT,ranchesofHopfpointswhichemallatefromacertaillsingularPointofatwopar:lmeterII()nlinearsystemwhereXisarealHillersspac(},Aabifllrcationparallleter,oranadditionalcontrolparameter,alldgisasnlootllmapping.\Nreassllllle(HI)gisA--synlnletric:thereexistsalillearoperators:X-Xsatisfying(I:identicaloperatorillX)Itiswellknottrnthat(1.2)irldllcestilesplittillgl)Th.firstauthorhasbeedsupportedbyar(>searchgralltoftileV'Olkswagen-StiftungWesaythatxiss… 相似文献