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81.
The crystal structure of a new non-centrosymmetric microporous fluorinated iron phosphate, (H3O)2[Fe4(H2O)2F4(PO4)2(HPO4)2](H2O), was determined by single crystal X-ray diffraction analysis and the result reveals that it belongs to the orthorhombic system with four molecules in the unit cell(space group P212121). Thus, the complex was characterized by powder X-ray diffraction, spectroscopic techniques(Fourier transform infrared and Fourier transform Raman) and 19F MAS NMR. The elemental analysis of the sample was also carried out. The chiral inorganic sheets, which stacked along[100] showed the presence of FeF2O4 as well as FeF2O3H2O octahedra, PO4 besides HPO4 tetrahedra, hydronium ions(H3O+) and isolated water molecules. Hirshfeld surface analysis, especially dnom surface and fingerprint plots, were used for decoding the intermolecular interactions in the crystal network and the contribution of component units for the construction of the 3D architecture. From the Hirshfeld surfaces and 2D fingerprint analysis, it was found that the subtle interactions, such as H…H associating the third intense interaction of all intercontacts, provide extra stabilization in addition to the presence of the strong hydrogen bonds mentioned above. 相似文献
82.
Numerical and experimental investigations of the dynamics of micromachined shallow arches (initially curved microbeams) and the possibility of using their dynamic snap-through motion for filtering purposes are presented. The considered MEMS arches are actuated by a DC electrostatic load along with an AC harmonic load. Their dynamics is examined numerically using a Galerkin-based reduced-order model when excited near both their first and third natural frequencies. Several simulation results are presented demonstrating interesting jumps and dynamic snap-through behavior of the MEMS arches and their attractive features for uses as band-pass filters, such as their sharp roll-off from pass-bands to stop-bands and their flat response. Experimental work is conducted to test arches realized of curved polysilicon microbeams when excited by DC and AC loads. Experimental data of the micromachined curved beams are shown for the softening and hardening behavior near the first and third natural frequencies, respectively, as well as dynamic snap-through motion. 相似文献
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Khadija Ben Hadj Hassen Kevin Gaubert Michel Vaultier Mathieu Pucheault 《Green Chemistry Letters and Reviews》2014,7(3):243-249
We describe a study of the gallium(III)-catalyzed 1,6-enynes cycloisomerization reaction in both homogeneous and heterogeneous conditions. With GaBr3 in homogeneous conditions, some particularities were observed in terms of selectivity compared to reported GaCl3-catalyzed reactions. The transfer of the reaction in heterogeneous conditions was realized by supporting Ga(III) salts onto montmorillonite. Both systems were compared based on reaction times, conversion, and selectivity and showed complementary activities. 相似文献
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Tausiff Mohammad Ouakad Hassen M. Alqahtani Hussain Alofi Abdurahman 《Nonlinear dynamics》2019,95(4):2907-2921
Nonlinear Dynamics - The nonlinear dynamic behavior of a resonant MEMS arch microbeam actuated by fringing electric actuation is investigated in this paper. The arch microbeam is loaded with DC and... 相似文献
88.
To improve the proton conduction of crystalline porous organic salts(CPOS-1), H2SO4 and H3PO4 were introduced into the channel to obtain H2SO4@CPOS-1 and H3PO4@CPOS-1. Compared to CPOS-1, the proton conductivities of H2SO4@CPOS-1 and H3PO4@CPOS-1 increased two orders of magnitude and one order of magnitude at 303 K and 100% RH, respectively. It can be attributed to the increasing concentration of the protons, which dissociates from the acids. 相似文献
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ABDELALI DAOUDI MOHAMED FILALI BABA SOUAD ELKHATTABI FRANÇOIS ROGEMOND HENRY CHERMETTE 《Molecular physics》2013,111(19):2929-2951
The electronic structure of the ScN and ScP molecules is a subject of controversy and turns out to be a challenging problem in quantum chemistry. We show that the ground-state electronic structure for both molecules depends critically on the choice of methods used which incorporate different ways of accounting for electron correlation. A parallel ab initio, DFT and TD-DFT study is performed for this purpose and uses sufficiently flexible basis sets able to reproduce accurate electronic structures, as well as correct spectroscopic constants. In the ab initio methodology, results have been obtained with methods such as Hartree-Fock (HF), M?ller-Plesset perturbation theory (MPn), direct configuration interaction (CI), quadratic configuration interaction (QC), coupled cluster configuration interaction (CC), complete active space self-consistent field (CASSCF) and multireference configuration interaction (CIPSI) methods. In the DFT methodology, various ‘pure’ and ‘hybrid’ density functionals are used and the corresponding results are compared to sophisticated ab initio methods and to available experimental data. All the methods used show that the ground state of both molecules is 1Σ+, but two electronic structure natures, 1Σ+ open-shell or 1Σ+ closed-shell, are competitive and depend on the method employed. All the ab initio methods based on a single determinant wavefunction suffer seriously in predicting clearly the exact nature of the ground state or its correct structural and spectroscopic parameters. However, the ab initio methods based on a multiconfigurational wavefunction appear to be successful in describing correctly, within one shot, the electronic structure and the molecular spectroscopic constants. The ground state, particularly for the ScN molecule, presents an unusual electronic structure: the presence of degenerate determinants, quasidegeneracy with other states and one avoided crossing in the region around the equilibrium distances. The bonding of the ground state is a two open-shell 1Σ+ state described as a π double bond and a Σ dative bond; the real triple bond 1Σ+ state, i.e. closed-shell state, is found to lie higher in energy. The potential energy curves of the lowlying electronic states, the derived electronic structures and various molecular spectroscopic constants are presented and discussed for each method employed. 相似文献