全文获取类型
收费全文 | 37038篇 |
免费 | 1403篇 |
国内免费 | 46篇 |
专业分类
化学 | 25213篇 |
晶体学 | 307篇 |
力学 | 706篇 |
数学 | 5317篇 |
物理学 | 6944篇 |
出版年
2023年 | 286篇 |
2022年 | 243篇 |
2021年 | 427篇 |
2020年 | 586篇 |
2019年 | 548篇 |
2018年 | 781篇 |
2017年 | 718篇 |
2016年 | 1362篇 |
2015年 | 1116篇 |
2014年 | 1124篇 |
2013年 | 2334篇 |
2012年 | 2608篇 |
2011年 | 2771篇 |
2010年 | 1631篇 |
2009年 | 1340篇 |
2008年 | 2306篇 |
2007年 | 2283篇 |
2006年 | 2026篇 |
2005年 | 1827篇 |
2004年 | 1509篇 |
2003年 | 1133篇 |
2002年 | 1032篇 |
2001年 | 770篇 |
2000年 | 695篇 |
1999年 | 501篇 |
1998年 | 389篇 |
1997年 | 292篇 |
1996年 | 421篇 |
1995年 | 276篇 |
1994年 | 283篇 |
1993年 | 318篇 |
1992年 | 296篇 |
1991年 | 223篇 |
1990年 | 198篇 |
1989年 | 191篇 |
1988年 | 174篇 |
1987年 | 171篇 |
1986年 | 170篇 |
1985年 | 225篇 |
1984年 | 195篇 |
1983年 | 156篇 |
1982年 | 144篇 |
1981年 | 149篇 |
1980年 | 105篇 |
1979年 | 140篇 |
1978年 | 117篇 |
1977年 | 110篇 |
1976年 | 121篇 |
1975年 | 103篇 |
1973年 | 118篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Martin Vohralík 《Comptes Rendus Mathematique》2004,339(7):525-528
We consider the lowest-order Raviart–Thomas mixed finite element method for elliptic problems on simplicial meshes in two or three space dimensions. This method produces saddle-point type problems for scalar and flux unknowns. We show how to easily eliminate the flux unknowns, which implies an equivalence between this method and a particular multi-point finite volume scheme, without any approximate numerical integration. We describe the stencil of the final matrix and give sufficient conditions for its symmetry and positive definiteness. We present a numerical example illustrating the performance of the proposed method. To cite this article: M. Vohralík, C. R. Acad. Sci. Paris, Ser. I 339 (2004). 相似文献
52.
We extend the previously found accelerated Kerr-Schild metrics for Einstein-Maxwell-null dust and Einstein-Born-Infeld-null dust equations to the cases including the cosmological constant. This way we obtain the generalization of the charged de Sitter metrics in static space-times. We also give a generalization of the zero acceleration limit of our previous Einstein-Maxwell and Einstein-Born-Infeld solutions. 相似文献
53.
The rate-dependent effects in metallic ferromagnetic materials with magnetization processes attributed to domain-walls motion were studied. The experimental method for eddy-current relaxation time determination was proposed. Some discrepancies between the data and theoretical predictions were observed and discussed. The origin of these discrepancies is accounted for by the decrease of viscous-type relaxation process as the rate of change of averaged magnetization is approaching zero. 相似文献
54.
In this paper we extend a result of Semrl stating that every 2-local automorphism of the full operator algebra on a separable infinite dimensional Hilbert space is an automorphism. In fact, besides separable Hilbert spaces, we obtain the same conclusion for the much larger class of Banach spaces with Schauder bases. The proof rests on an analogous statement concerning the 2-local automorphisms of matrix algebras for which we present a short proof. The need to get such a proof was formulated in Semrl's paper.
55.
56.
The physico-chemical properties and reactivity tested by hydrogen reduction have been studied for two series of NiO-ZnO mixed oxides of various composition. The solid nickel oxide or zinc oxide in interaction with the solution of nitrate of the second component were used as the precursors in each series. The differences in some physico-chemical parameters of the samples in both series were correlated with their reduction behaviour, followed both in iso- and non-isothermal regime. Moreower, the influence of various factors modifying the reactivity of mixed oxides was also investigated and the results were compared with those obtained from earlier studied analogous systems of quite different origin.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
57.
M. C. Caracoche J. A. Martínez P. C. Rivas M. A. Taylor A. F. Pasquevich S. Barolin O. A. de Sanctis 《Hyperfine Interactions》2007,179(1-3):87-93
The hyperfine quadrupole interaction at Hf sites in films and powders of 14 mol% CaO–HfO2 and 20 mol% CaO–HfO2 has been determined as a function of temperature. Results indicate the formation of a cubic solid solution and other microstructures assigned to the ?1 (CaHf4O9) and ?2 (Ca6Hf19O44) phases. Dynamical effects on the electric field gradient reveal the existence of oxygen vacancies movements in the solid solution. The thermal behavior of the relaxation constant observed in films allowed the determination of activation energies of 0.54 eV and 0.70 eV for the 14 mol% and 20 mol% CaO doped hafnias, respectively. The influence of the microdomains and the stability of the cubic solid solution are discussed. 相似文献
58.
Mátyás Bognár 《Acta Mathematica Hungarica》2004,102(1-2):37-84
The following generalization of the Hahn-Mazurkiewicz theorem is proved: Let (E,e) be a locally compact locally connected metric space. Let M be a continuum in this space and let d,e∈ M. Then there is a continuous mapping f: [0,1]→E such that f(0) = d, f(1)= e and M⊂f([0,1]). Also some corollaries of this theorem are proved. 相似文献
59.
B. G. Konopelchenko L. Martínez Alonso E. Medina 《Theoretical and Mathematical Physics》2007,151(3):820-830
Based on the Lenard relations, we completely classify integrable deformations of general algebraic curves. We construct the
general solution of the Lenard relation from the invariance condition with respect to an element of the Galois group of the
curve. We give some examples and also some associated conservation laws.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 151, No. 3, pp. 458–469, June, 2007. 相似文献
60.
Lubomír Kubáček 《Mathematica Slovaca》2007,57(6):571-588
The multivariate model, where not only parameters of the mean value of the observation matrix, but also some other parameters
occur in constraints, is considered in the paper. Some basic inference is presented under the condition that the covariance
matrix is either unknown, or partially unknown, or known.
Supported by the grant of the Council of Czech Republic MSM 6 198 959 214. 相似文献