全文获取类型
收费全文 | 106909篇 |
免费 | 6090篇 |
国内免费 | 3636篇 |
专业分类
化学 | 45091篇 |
晶体学 | 1113篇 |
力学 | 8353篇 |
综合类 | 136篇 |
数学 | 34642篇 |
物理学 | 27300篇 |
出版年
2024年 | 135篇 |
2023年 | 692篇 |
2022年 | 1203篇 |
2021年 | 1292篇 |
2020年 | 1392篇 |
2019年 | 1375篇 |
2018年 | 11301篇 |
2017年 | 11049篇 |
2016年 | 7475篇 |
2015年 | 2332篇 |
2014年 | 2231篇 |
2013年 | 2693篇 |
2012年 | 6540篇 |
2011年 | 13174篇 |
2010年 | 7380篇 |
2009年 | 7694篇 |
2008年 | 8441篇 |
2007年 | 10335篇 |
2006年 | 1823篇 |
2005年 | 2542篇 |
2004年 | 2469篇 |
2003年 | 2703篇 |
2002年 | 1742篇 |
2001年 | 824篇 |
2000年 | 751篇 |
1999年 | 742篇 |
1998年 | 700篇 |
1997年 | 640篇 |
1996年 | 685篇 |
1995年 | 539篇 |
1994年 | 416篇 |
1993年 | 372篇 |
1992年 | 330篇 |
1991年 | 286篇 |
1990年 | 251篇 |
1989年 | 209篇 |
1988年 | 150篇 |
1987年 | 136篇 |
1986年 | 161篇 |
1985年 | 119篇 |
1984年 | 79篇 |
1983年 | 80篇 |
1982年 | 69篇 |
1981年 | 60篇 |
1980年 | 53篇 |
1979年 | 48篇 |
1914年 | 45篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The present paper devotes to the long-time behavior of a class of reaction diffusion equations with delays under Dirichlet boundary conditions. The stability and global attractability for the zero solution are provided, and the existence, stability and attractability for the positive stationary solution are also obtained. 相似文献
82.
83.
Dual fractional cutting plane algorithms, in which cutting planes are used to iteratively tighten a linear relaxation of an integer program,
are well-known and form the basis of the highly successful branch-and-cut method. It is rather less well-known that various primal cutting plane algorithms were developed in the 1960s, for example by Young. In a primal algorithm, the main role of the cutting
planes is to enable a feasible solution to the original problem to be improved. Research on these algorithms has been almost
non-existent.
In this paper we argue for a re-examination of these primal methods. We describe a new primal algorithm for pure 0-1 problems based on strong valid inequalities and give some encouraging computational results. Possible extensions to the case of general
mixed-integer programs are also discussed. 相似文献
84.
Yasuyuki Kawahigashi 《Communications in Mathematical Physics》2002,226(2):269-287
We study the recent construction of subfactors by Rehren which generalizes the Longo–Rehren subfactors. We prove that if
we apply this construction to a non-degenerately braided subfactor N⊂M and α±-induction, then the resulting subfactor is dual to the Longo–Rehren subfactor M⊗M
opp⊂R arising from the entire system of irreducible endomorphisms of M resulting from αplusmn;-induction. As a corollary, we solve a problem on existence of braiding raised by Rehren negatively. Furthermore, we generalize
our previous study with Longo and Müger on multi-interval subfactors arising from a completely rational conformal net of factors
on S
1 to a net of subfactors and show that the (generalized) Longo–Rehren subfactors and α-induction naturally appear in this context.
Received: 11 September 2001 / Accepted: 7 October 2001 相似文献
85.
Julio Castellanos 《Mathematische Zeitschrift》2002,239(4):777-802
We consider complete ideals supported on finite sequences of infinitely near points, in regular local rings with dimensions
greater than two. We study properties of factorizations in Lipman special *-simple complete ideals. We relate it to a type
of proximity, linear proximity, of the points, and give conditions in order to have unique factorization. Several examples
are presented.
Received: 2 February 2000 / in final form: 14 March 2001 / Published online: 18 January 2002 相似文献
86.
87.
88.
Alexander Krasnosel'skii Dmitrii Rachinskii 《NoDEA : Nonlinear Differential Equations and Applications》2002,9(1):93-115
We consider autonomous systems with a nonlinear part depending on a parameter and study Hopf bifurcations at infinity. The
nonlinear part consists of the nonlinear functional term and the Prandtl--Ishlinskii hysteresis term. The linear part of the
system has a special form such that the close-loop system can be considered as a hysteresis perturbation of a quasilinear
Hamiltonian system. The Hamiltonian system has a continuum of arbitrarily large cycles for each value of the parameter. We
present sufficient conditions for the existence of bifurcation points for the non-Hamiltonian system with hysteresis. These
bifurcation points are determined by simple characteristics of the hysteresis nonlinearity. 相似文献
89.
Claudia-Elisabeth Wulz 《Czechoslovak Journal of Physics》2002,52(3):C155-C170
The principal physics goals of the Compact Muon Solenoid experiment under construction at the Large Hadron Collider at CERN in Geneva are reviewed. Procedures to search for the Standard Model Higgs boson, supersymmetric Higgses and other supersymmetric particles are described. 相似文献
90.
A design of diode-pumped high-efficiency Nd:YVO4/LBO red laser is reported. Using critical phase-matching (CPM) LBO, 671 nm red laser was obtained from 1342 nm light by intracavity frequency doubling. With an incident pump laser of 800 mW, using type-I and type-II CPM LBO, 97 and 52 mWTEM00 mode red laser outputs were obtained, with optical-to-optical conversion efficiencies of up to 12.1% and 6.5%, respectively. 相似文献