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91.
We consider quantum field theoretical models inn dimensional space-time given by interaction densities which are bounded functions of an ultraviolet cut-off boson field. Using methods of euclidean Markov field theory and of classical statistical mechanics, we construct the infinite volume imaginary and real time Wightman functions as limits of the corresponding quantities for the space cut-off models. In the physical Hilbert space, the space-time translations are represented by strongly continuous unitary groups and the generator of time translationsH is positive and has a unique, simple lowest eigenvalue zero, with eigenvector , which is the unique state invariant under space-time translations. The imaginary time Wightman functions and the infinite volume vacuum energy density are given as analytic functions of the coupling constant. The Wightman functions have cluster properties also with respect to space translations. 相似文献
92.
Sergio Albeverio Raphael Høegh-krohn 《Journal of Mathematical Analysis and Applications》1984,101(2):491-513
Schrödinger operators on L2(3) of the form ?Δ + Vλ with potentials Vλ real-analytic in λ are discussed. The analytic structure in Vλ and k (with k2 the energy variable) of the resolvent kernel, the eigenvalues and resonances is exhibited and we obtain in particular convergent perturbation expansions for the resonances and the corresponding resonance functions. The lower order expansion coefficients are computed explicitly. The resonances and the corresponding functions are also computed for a particle moving under the action of n point interactions. This gives asymptotic low energy information about Schrödinger Hamiltonians with short range potentials. The perturbation theory of resonances, eigenvalues and of the corresponding functions for Hamiltonians describing n point interactions perturbed by a potential is also given. 相似文献
93.
Sergio A. Celani 《Central European Journal of Mathematics》2003,1(4):561-572
In this paper we shall give a topological representation for Hilbert algebras that extend the topological representation given
by A. Diego in [4]. For implicative semilattices this representation gives a full duality. We shall also consider the representation
for Boolean ring. 相似文献
94.
Engin Büyükaşık Edgar Enochs J. R. García Rozas Gizem Kafkas-Demirci Sergio López-Permouth Luis Oyonarte 《代数通讯》2018,46(2):764-779
Relative notions of flatness are introduced as a mean to gauge the extent of the flatness of any given module. Every module is thus endowed with a flatness domain and, for every ring, the collection of flatness domains of all of its modules is a lattice with respect to class inclusion. This lattice, the flatness profile of the ring, allows us, in particular, to focus on modules which have a smallest flatness domain (namely, one consisting of all regular modules.) We establish that such modules exist over arbitrary rings and we call them Rugged Modules. Rings all of whose (cyclic) modules are rugged are shown to be precisely the von Neumann regular rings. We consider rings without a flatness middle class (i.e., rings for which modules must be either flat or rugged.) We obtain that, over a right Noetherian ring every left module is rugged or flat if and only if every right module is poor or injective if and only if R = S×T, where S is semisimple Artinian and T is either Morita equivalent to a right PCI-domain, or T is right Artinian whose Jacobson radical properly contains no nonzero ideals. Character modules serve to bridge results about flatness and injectivity profiles; in particular, connections between rugged and poor modules are explored. If R is a ring whose regular left modules are semisimple, then a right module M is rugged if and only if its character left module M+ is poor. Rugged Abelian groups are fully characterized and shown to coincide precisely with injectively poor and projectively poor Abelian groups. Also, in order to get a feel for the class of rugged modules over an arbitrary ring, we consider the homological ubiquity of rugged modules in the category of all modules in terms of the feasibility of rugged precovers and covers for arbitrary modules. 相似文献
95.
Sergio Albeverio Yuri Kondratiev Roman Nikiforov Grygoriy Torbin 《Bulletin des Sciences Mathématiques》2014
The paper is devoted to the study of fractal properties of subsets of the set of non-normal numbers with respect to Rényi f -expansions generated by continuous increasing piecewise linear functions defined on [0,+∞). All such expansions are expansions for real numbers generated by infinite linear IFS f={f0,f1,…,fn,…} with the following list of ratios Q∞=(q0,q1,…,qn,…). 相似文献
96.
We will focus on the existence of nontrivial solutions to the following Hamiltonian elliptic system where are numbers belonging to the interval [0, 2), V is a continuous potential bounded below on by a positive constant and the functions f and g possess exponential growth range established by Trudinger–Moser inequalities in Lorentz–Sobolev spaces. The proof involves linking theorem and a finite‐dimensional approximation. 相似文献
97.
Mega MS Allegrini P Grigolini P Latora V Palatella L Rapisarda A Vinciguerra S 《Physical review letters》2003,90(18):188501
We study the statistical properties of time distribution of seismicity in California by means of a new method of analysis, the diffusion entropy. We find that the distribution of time intervals between a large earthquake (the main shock of a given seismic sequence) and the next one does not obey Poisson statistics, as assumed by the current models. We prove that this distribution is an inverse power law with an exponent mu=2.06+/-0.01. We propose the long-range model, reproducing the main properties of the diffusion entropy and describing the seismic triggering mechanisms induced by large earthquakes. 相似文献
98.
Michele Di Cristo Luca Rondi Sergio Vessella 《Annali di Matematica Pura ed Applicata》2006,185(2):223-255
We treat the stability issue for an inverse problem arising from non-destructive evaluation by thermal imaging. We consider
the determination of an unknown portion of the boundary of a thermic conducting body by overdetermined boundary data for a
parabolic initial-boundary value problem. We obtain that when the unknown part of the boundary is a priori known to be smooth,
the data are as regular as possible and all possible measurements are taken into account, the problem is exponentially ill-posed.
Then, we prove that a single measurement with some a priori information on the unknown part of the boundary and minimal assumptions
on the data, in particular on the thermal conductivity, is enough to have stable determination of the unknown boundary. Given
the exponential ill-posedness, the stability estimate obtained is optimal.
AMS 2000 Mathematics Subject Classification. Primary 35R30, Secondary 35B60, 33C90 相似文献
99.
Guillermo Durán Min Chih Lin Sergio Mera Jayme L. Szwarcfiter 《Annals of Operations Research》2008,157(1):37-45
A clique-transversal of a graph G is a subset of vertices intersecting all the cliques of G. It is NP-hard to determine the minimum cardinality τ
c
of a clique-transversal of G. In this work, first we propose an algorithm for determining this parameter for a general graph, which runs in polynomial
time, for fixed τ
c
. This algorithm is employed for finding the minimum cardinality clique-transversal of
[`(3K2)]\overline{3K_{2}}
-free circular-arc graphs in O(n
4) time. Further we describe an algorithm for determining τ
c
of a Helly circular-arc graph in O(n) time. This represents an improvement over an existing algorithm by Guruswami and Pandu Rangan which requires O(n
2) time. Finally, the last proposed algorithm is modified, so as to solve the weighted version of the corresponding problem,
in O(n
2) time. 相似文献
100.
Gaussian distributions on infinite-dimensional p-adic spaces are introduced and the corresponding L2-spaces of p-adic-valued square integrable functions are constructed. Representations of the infinite-dimensional Weyl group are realized in p-adic L2-spaces. There is a formal analogy with the usual Segal representation. But there is also a large topological difference: parameters of the p-adic infinite-dimensional Weyl group are defined only on some balls (these balls are additive subgroups). p-adic Hilbert space representations of quantum Hamiltonians for systems with an infinite number of degrees of freedom are constructed. Many Hamiltonians with potentials which are too singular to exist as functions over reals are realized as bounded symmetric operators in L2-spaces with respect to a p-adic Gaussian distribution. 相似文献