全文获取类型
收费全文 | 288473篇 |
免费 | 1900篇 |
国内免费 | 853篇 |
专业分类
化学 | 121399篇 |
晶体学 | 4042篇 |
力学 | 17095篇 |
综合类 | 5篇 |
数学 | 63379篇 |
物理学 | 85306篇 |
出版年
2018年 | 18072篇 |
2017年 | 18702篇 |
2016年 | 10241篇 |
2015年 | 2612篇 |
2014年 | 1739篇 |
2013年 | 5241篇 |
2012年 | 10684篇 |
2011年 | 25152篇 |
2010年 | 14569篇 |
2009年 | 14780篇 |
2008年 | 19981篇 |
2007年 | 25336篇 |
2006年 | 4514篇 |
2005年 | 12413篇 |
2004年 | 8425篇 |
2003年 | 8365篇 |
2002年 | 5431篇 |
2001年 | 3975篇 |
2000年 | 3254篇 |
1999年 | 2382篇 |
1998年 | 2109篇 |
1997年 | 2032篇 |
1996年 | 2119篇 |
1995年 | 1971篇 |
1994年 | 1704篇 |
1993年 | 1704篇 |
1992年 | 1867篇 |
1991年 | 1879篇 |
1990年 | 1795篇 |
1989年 | 1807篇 |
1988年 | 1831篇 |
1987年 | 1807篇 |
1986年 | 1716篇 |
1985年 | 2269篇 |
1984年 | 2396篇 |
1983年 | 2020篇 |
1982年 | 2340篇 |
1981年 | 2150篇 |
1980年 | 2198篇 |
1979年 | 2207篇 |
1978年 | 2331篇 |
1977年 | 2151篇 |
1976年 | 2197篇 |
1975年 | 2119篇 |
1974年 | 1958篇 |
1973年 | 2218篇 |
1972年 | 1341篇 |
1971年 | 1010篇 |
1968年 | 1163篇 |
1967年 | 1140篇 |
排序方式: 共有10000条查询结果,搜索用时 703 毫秒
131.
132.
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
133.
134.
We call a one-way infinite word w over a finite alphabet (ρ,l)-repetitive if all long enough prefixes of w contain as a suffix a ρth power (or more generally a repetition of order ρ) of a word of length at most l. We show that each (2,4)-repetitive word is ultimately periodic, as well as that there exist continuum many, and hence also nonultimately periodic, (2,5)-repetitive words. Further, we characterize nonultimately periodic (2,5)-repetitive words both structurally and algebraically. 相似文献
135.
136.
Annegret K. Wagler 《Mathematical Methods of Operations Research》2002,56(1):127-149
An edge e of a perfect graph G is critical if G−e is imperfect. We would like to decide whether G−e is still “almost perfect” or already “very imperfect”. Via relaxations of the stable set polytope of a graph, we define two
superclasses of perfect graphs: rank-perfect and weakly rank-perfect graphs. Membership in those two classes indicates how
far an imperfect graph is away from being perfect. We study the cases, when a critical edge is removed from the line graph
of a bipartite graph or from the complement of such a graph. 相似文献
137.
Possible Loss and Recovery of Gibbsianness¶During the Stochastic Evolution of Gibbs Measures 总被引:1,自引:1,他引:0
A.C.D. van Enter R. Fernández F. den Hollander F. Redig 《Communications in Mathematical Physics》2002,226(1):101-130
We consider Ising-spin systems starting from an initial Gibbs measure ν and evolving under a spin-flip dynamics towards a
reversible Gibbs measure μ≠ν. Both ν and μ are assumed to have a translation-invariant finite-range interaction. We study
the Gibbsian character of the measure νS(t) at time t and show the following:
(1) For all ν and μ, νS(t) is Gibbs for small t.
(2) If both ν and μ have a high or infinite temperature, then νS(t) is Gibbs for all t > 0.
(3) If ν has a low non-zero temperature and a zero magnetic field and μ has a high or infinite temperature, then νS(t) is Gibbs for small t and non-Gibbs for large t.
(4) If ν has a low non-zero temperature and a non-zero magnetic field and μ has a high or infinite temperature, then νS(t) is Gibbs for small t, non-Gibbs for intermediate t, and Gibbs for large t.
The regime where μ has a low or zero temperature and t is not small remains open. This regime presumably allows for many different scenarios.
Received: 26 April 2001 / Accepted: 10 October 2001 相似文献
138.
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
139.
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
140.
D.W. Mueller JrA.L. Crosbie 《Journal of Quantitative Spectroscopy & Radiative Transfer》2002,74(1):43-68
Three-dimensional radiative transfer in an anisotropic scattering medium exposed to spatially varying, collimated radiation is studied. The generalized reflection function for a semi-infinite medium with a very general scattering phase function is the focus of this investigation. An integral transform is used to reduce the three-dimensional transport equation to a one-dimensional form, and a modified Ambarzumian's method is applied to formulate a nonlinear integral equation for the generalized reflection function. The integration is over both the polar and azimuthal angles; hence, the integral equation is said to be in the double-integral form. The double-integral, reflection function formulation can handle a variety of anisotropic phase functions and does not require an expansion of the phase function in a Legendre polynomial series. Complicated kernel transformations of previous single-integral studies are eliminated. Single and double scattering approximations are developed. Numerical results are presented for a Rayleigh phase function to illustrate the computational characteristics of the method and are compared to results obtained with the single-integral method. Agreement between the two approaches is excellent; however, as the transform variable increases beyond five the number of quadrature points required for the double-integral method to produce accurate solutions significantly increases. A new interpolation scheme produces accurate results when the transform variable is large. 相似文献