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81.
We show that string models with low energy supersymmetry which accommodate the fermion mass hierarchy generally give nonuniversal soft trilinear couplings (A terms). In conjunction with the apparently large Cabibbo-Kobayashi-Maskawa (CKM) phase, this results in large fermion electric dipole moments (EDMs) even in the absence of CP violating phases in the supersymmetry breaking auxiliary fields and the micro term. Nonobservation of the EDMs therefore implies that strings select special flavor and/or supersymmetry breaking patterns. 相似文献
82.
Changes of the magnetic properties of ferromagnetic Co particles deposited on the radical31 x radical31R +/- 9 degrees reconstructed alpha-Al2O3(0001) as well as on a thin alumina film grown on a NiAl(110) substrate were investigated as a function of thermal annealing. On the thin film changes of the magnetic response were found above 500 K which correlates with changes in the particle size distribution. Annealing to 870 K leads to a permeation of the metal though the oxide film which causes significant changes in the ferromagnetic resonance response. On the alpha-Al2O3 single crystal sintering of particles requires temperatures above 600 K being about 100 K higher as compared to the thin alumina film. For large clusters intraparticle redistribution takes place already below 600 K a phenomenon not observed for the small clusters. In addition, a significant dependence of the measured g values from the substrate as well as the thermal treatment is found which can be understood in terms of the structural properties of the systems. 相似文献
83.
Echeverría J Carreras A Casanova D Alemany P Alvarez S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(1):359-367
We analyze in this article the degree to which different groups of atoms retain local symmetries when assembled in a molecule. This study is carried out by applying continuous symmetry measures to several families of mixed sandwiches, a variety of piano-stool molecules, and several organic groups. An analysis of the local symmetry of the electron density shows that, sandwiched between two regions of different symmetry that correspond to the ligand sets, its symmetry is cylindrical at the central metal atom. 相似文献
84.
Qureshi N Steffens P Drees Y Komarek AC Lamago D Sidis Y Harnagea L Grafe HJ Wurmehl S Büchner B Braden M 《Physical review letters》2012,108(11):117001
Magnetic correlations in superconducting LiFeAs were studied by elastic and by inelastic neutron-scattering experiments. There is no indication for static magnetic ordering, but inelastic correlations appear at the incommensurate wave vector (0.5±δ,0.5-/+δ,0) with δ~0.07 slightly shifted from the commensurate ordering observed in other FeAs-based compounds. The incommensurate magnetic excitations respond to the opening of the superconducting gap by a transfer of spectral weight. 相似文献
85.
86.
Necessary conditions for existence of a (v,k,λ) perfect Mendelsohn design (or PMD) are v k and λv(v − 1) ≡ 0 mod k. When k = 7, this condition is satisfied if v ≡ 0 or 1 mod 7 and v 7 when λ 0 mod 7 and for all v 7 when λ ≡ 0 mod 7. Bennett, Yin and Zhu have investigated the existence problem for k = 7, λ = 1 and λ even; here we provide several improvements on their results and also investigate the situation for λ odd. We reduce the total number of unknown (v,7,λ)-PMDs to 36,31 for λ = 1 and 5 for λ > 1. In particular, v = 294 is the largest unknown case for λ = 1, and the only unknown cases for λ > 1 are for v = 42, λ [2,3,5,9] and v = 18, λ = 7. 相似文献
87.
In this article, we introduce a novel Bayesian approach for linking multiple social networks in order to discover the same real world person having different accounts across networks. In particular, we develop a latent model that allows us to jointly characterize the network and linkage structures relying on both relational and profile data. In contrast to other existing approaches in the machine learning literature, our Bayesian implementation naturally provides uncertainty quantification via posterior probabilities for the linkage structure itself or any function of it. Our findings clearly suggest that our methodology can produce accurate point estimates of the linkage structure even in the absence of profile information, and also, in an identity resolution setting, our results confirm that including relational data into the matching process improves the linkage accuracy. We illustrate our methodology using real data from popular social networks such as Twitter , Facebook , and YouTube . 相似文献
88.
A method is given for constructing Lyapunov Functionals for dynamical systems governed by partial differential equations. The functionals are obtained as path integrals in a suitably chosen state space of a generalized gradient operator, and the method may be viewed as an extension to infinite dimensional systems of the variable gradient technique. Some of the fundamental concepts underlying the formalism are reviewed, and examples of applications to some linear, non-linear and hybrid systems are given. 相似文献
89.
Abel Zúñiga-Moreno Carmen M. Reza-San Germán Oscar G. Rojas-Valencia Elizabeth P. Juárez-Camacho 《Journal of solution chemistry》2011,40(4):621-631
Densities of the binary mixture of nonane with decane were measured at temperatures from 283.15 to 353.15 K at atmospheric
pressure (0.7 atm). Measurements have been made over the full range of compositions and for the pure compounds by using a
vibrating-tube densimeter (VTD). Excess molar volumes have been obtained from these experimental results and were fitted to
a Redlich–Kister type expansion. The excess molar volumes exhibit small positive and small negative deviations from ideal
behavior in the temperature interval studied. Partial molar volumes and partial molar volumes at infinite dilution have been
determined for each component. 相似文献
90.
Berthe J Garcia JM Ocando E Kato T Saffon-Merceron N De Cózar A Cossío FP Baceiredo A 《Journal of the American Chemical Society》2011,133(40):15930-15933
The synthesis of the first isolable C-phosphino-Ge-aminogermyne, stabilized by a phosphine ligand, has been achieved. X-ray diffraction analysis indicates a quite long Ge-C bond whose length is between that of a single and a double bond but consistent with the theoretically predicted values for a germyne bearing π-donating substituents. The isomerization of this germyne derivative affords a new stable N-heterocyclic germylene through migration of the original phosphine ligand from germanium to the carbon center. 相似文献