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991.
We study those functions that can be written as a finite sum of periodic integer valued functions. On ℤ we give three different
characterizations of these functions. For this we prove that the existence of a real valued periodic decomposition of a ℤ
→ ℤ function implies the existence of an integer valued periodic decomposition with the same periods. This result depends
on the representation of the greatest common divisor of certain polynomials with integer coefficients as a linear combination
of the given polynomials where the coefficients also belong to ℤ[x]. We give an example of an ℤ → {0, 1} function that has a bounded real valued periodic decomposition but does not have a
bounded integer valued periodic decomposition with the same periods. It follows that the class of bounded ℤ → ℤ functions
has the decomposition property as opposed to the class of bounded ℝ → ℤ functions. If the periods are pairwise commensurable
or not prescribed, then we get more general results.
Supported by OTKA grants T 43623 and K 61908. 相似文献
992.
Given a continuous function f defined on the unit cube of R~n and a convexfunction _t,_t(0)-0,_t(x)>0,for x>0,we prove that the set ofbest L~(t)-approximations by monotone functions has exactly one elementft,which is also a continuous function.Moreover if the family of convexfunctions {_t}t>0 converges uniformly on compact sets to a function _0,then the best approximation f_t→f_0 uniformly,as t→0,where fo is thebest approximation of f within the Orlicz space L~(0) The best approxima-tions{f_t}are obtained as well as minimizing integrals or the Luxemburgnorm 相似文献
993.
994.
Germán Fonseca Felipe Linares Gustavo Ponce 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2013
We study the initial value problem associated to the dispersion generalized Benjamin–Ono equation. Our aim is to establish persistence properties of the solution flow in weighted Sobolev spaces and to deduce from them some sharp unique continuation properties of solutions to this equation. In particular, we shall establish optimal decay rate for the solutions of this model. 相似文献
995.
In this paper, a directional distance approach is proposed to deal with network DEA problems in which the processes may generate not only desirable final outputs but also undesirable outputs. The proposed approach is applied to the problem of modelling and benchmarking airport operations. The corresponding network DEA model considers two process (Aircraft Movement and Aircraft Loading) with two final outputs (Annual Passenger Movement and Annual Cargo handled), one intermediate product (Aircraft Traffic Movements) and two undesirable outputs (Number of Delayed Flights and Accumulated Flight Delays). The proposed approach has been applied to Spanish airports data for year 2008 comparing the computed directional distance efficiency scores with those obtained using a conventional, single-process directional distance function approach. From this comparison, it can be concluded that the proposed network DEA approach has more discriminatory power than its single-process counterpart, uncovering more inefficiencies and providing more valid results. 相似文献
996.
An efficient solution approach for real-world driver scheduling problems in urban bus transportation
The driver scheduling problem in public transportation is defined in the following way. There is a set of operational tasks, and the goal is to define the sequence of these tasks as shifts in such a way that every task must be assigned to a shift without overlapping. In real-world situations several additional constraints need to be considered, which makes large practical problems challenging to be solved efficiently. In practice it is also an important request with respect to a public transportation scheduling system to offer several versions of quasi-optimal solutions. In this paper we present an efficient driver scheduling solution methodology which is flexible in the above sense. 相似文献
997.
José Ernesto Falcón Dieguez Pablo Rodi Manuel A. Lores Guevara Ana Maria Gennaro 《Applied magnetic resonance》2010,38(4):443-453
An enhanced hemoglobin–membrane association has been previously documented in sickle cell anemia. However, it is not known
how this interaction is modified during the hemoglobin S polymerization process. In this work, we use a model of reconstituted
erythrocytes from ghost membranes whose cytoskeleton proteins had been previously labeled with the 4-maleimido Tempo spin
label, and that were subsequently resealed with hemoglobin S or A solutions. Using electron paramagnetic resonance spectroscopy,
we studied the time dependence of the spectral W/S parameter, indicative of the conformational state of cytoskeleton proteins
(mainly spectrin) under spontaneous deoxygenation, with the aim of detecting the eventual effects due to hemoglobin S polymerization.
The differences observed in the temporal behavior of W/S in erythrocytes reconstituted with both hemoglobins were considered
as experimental evidence of an increment in hemoglobin S–membrane interaction as a result of the polymerization process of
hemoglobin S under spontaneous deoxygenation. 相似文献
998.
The general form of the anisotropy parameter of the expansion for Bianchi type-III metric is obtained in the presence of a
single diagonal imperfect fluid with a dynamically anisotropic equation of state parameter and a dynamical energy density
in general relativity. A special law is assumed for the anisotropy of the fluid which reduces the anisotropy parameter of
the expansion to a simple form (D μ H-2V-2{\Delta\propto H^{-2}V^{-2}}, where Δ is the anisotropy parameter, H is the mean Hubble parameter and V is the volume of the universe). The exact solutions of the Einstein field equations, under the assumption on the anisotropy
of the fluid, are obtained for exponential and power-law volumetric expansions. The isotropy of the fluid, space and expansion
are examined. It is observed that the universe can approach to isotropy monotonically even in the presence of an anisotropic
fluid. The anisotropy of the fluid also isotropizes at later times for accelerating models and evolves into the well-known
cosmological constant in the model for exponential volumetric expansion. 相似文献
999.
Flavia Bonomo Guillermo Durán Martín D. Safe Annegret K. Wagler 《Discrete Applied Mathematics》2013,161(13-14):1925-1942
A graph is balanced if its clique-matrix contains no edge–vertex incidence matrix of an odd chordless cycle as a submatrix. While a forbidden induced subgraph characterization of balanced graphs is known, there is no such characterization by minimal forbidden induced subgraphs. In this work, we provide minimal forbidden induced subgraph characterizations of balanced graphs restricted to graphs that belong to one of the following graph classes: complements of bipartite graphs, line graphs of multigraphs, and complements of line graphs of multigraphs. These characterizations lead to linear-time recognition algorithms for balanced graphs within the same three graph classes. 相似文献
1000.
José María Gómez-Ros Roberto Bedogni Montserrat Moraleda Ana Romero Antonio Delgado Adolfo Esposito 《Radiation measurements》2010,45(10):1220-1223
This communication describes a new neutron spectrometer consisting of pairs of 7Li and 6Li based thermoluminescent dosemeters (MCP-6, MCP-7) located at selected positions within a single moderating polyethylene sphere. The spatial arrangement of the dosemeters has been designed using the MCNPX Monte Carlo code to calculate the response matrix in order to obtain a nearly isotropic response for neutrons in the energy range up to 20 MeV. A partial validation of the calculated response matrix has been performed with the calibrated 241Am–Be neutron source at the INFN–LNF Laboratory, using the shadow cone technique. 相似文献