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171.
Dr. Santanab Giri Swayamprabha Behera Prof. Puru Jena 《Angewandte Chemie (International ed. in English)》2014,53(50):13916-13919
Most electrolytes currently used in Li‐ion batteries contain halogens, which are toxic. In the search for halogen‐free electrolytes, we studied the electronic structure of the current electrolytes using first‐principles theory. The results showed that all current electrolytes are based on superhalogens, i.e., the vertical electron detachment energies of the moieties that make up the negative ions are larger than those of any halogen atom. Realizing that several superhalogens exist that do not contain a single halogen atom, we studied their potential as effective electrolytes by calculating not only the energy needed to remove a Li+ ion but also their affinity towards H2O. Several halogen‐free electrolytes are identified among which Li(CB11H12) is shown to have the greatest potential. 相似文献
172.
173.
Good and adhesive semiconducting films of ZnO (∼ 100–1100 nm) were deposited over planar borosilicate glass by spray pyrolysis
and dip & dry method. The films were characterized by X-ray diffraction and optical absorption measurements. The band gap
of these films were found to be 3.21 eV and the films were randomly oriented having average crystallite sizes of 20 to 25
nm.
Paper presented at the 2nd International Conference on Ionic Devices, Anna University, Chennai, India, Nov. 28–30, 2003. 相似文献
174.
175.
A simple three-parameter density dependent effective interaction is used to study the properties of nuclear matter, neutron matter and some bulk properties such as ground state energies and rms charge radii of three double-closed shell nuclei4He,16O and40Ca. The three parameters of the effective interaction are determined by requiring to fit the binding energy and density of infinite nuclear matter at saturation density as well as ground state energy of16O in the first order perturbation theory. This interaction gives correct saturation in nuclear matter with a value of 283 MeV for compressibility. The symmetry coefficienta
T
atk
F=1·36 fm–1 is 28·58 MeV. The energy per particle in neutron matter is calculated in the range of nuclear matter densities and it compares well with those ofNemeth andSprung. Groundstate energies and rms charge radii of4He,16O and40Ca are calculated using oscillator eigen functions as single particle wave functions. Results for ground state energies are in good agreement with empirical values and rms charge radii are slightly better than those obtained byMoszkowski with the MDI.The authors are thankful to the Computer Centre, Utkal University, Bhubaneswar for providing computational facilities for this work. 相似文献
176.
The modes of vibration of a three impurity cluster in a diatomic linear chain is studied. The configuration of the three impurity atoms is such that two of these go into next nearest neighbour sites in one of the sub-lattices whereas the third occupies the central in between site in the other sub-lattice. New local, gap and inband modes are seen to exist, besides the ones corresponding to the impurity pairs. A new feature which appears is that the frequencies of some of the pair modes remain totally unaffected in the presence of the third impurity atom. 相似文献
177.
The question of the occurrence of two-phonon bound states in imperfect crystals is investigated. It is shown that the anharmonicity
mediated two-phonon bound state which is present in perfect crystals gets modified due to the presence of impurities. Moreover,
the possibility of the occurrence of a purely impurity mediated two-phonon bound state is demonstrated. The bound state frequencies
are calculated using the simple Einstein oscillator model for the host phonons. The two-phonon density of states for the imperfect
crystal thus obtained has peaks at the combination and difference frequencies of two host phonons besides the peaks at the
bound state frequencies. For a perfect crystal the theory predicts a single peak at the two-phonon bound state frequency in
conformity with experimental observations and other theoretical calculations. Experimental data on the two-phonon infrared
absorption and Raman scattering from mixed crystals of GA1−c
Al
c
P and Ge1−c
Si
c
are analysed to provide evidence in support of impurity-mediated two-phonon bound states. The relevance of the zero frequency
(difference spectrum) peak to the central peak observed in structural phase transitions, is conjectured;
This work is a part of the thesis to be submitted by one of the authors (SS) in partial fulfilment of the degree of Doctor
of Philosophy to Utkal University, Bhubaneswar, India. 相似文献
178.
Jiao J Kanellopoulos J Behera B Jiang Y Huang J Reddy Marthala VR Ray SS Wang W Hunger M 《The journal of physical chemistry. B》2006,110(28):13812-13818
The effect of adsorbate molecules on the quadrupolar interaction of framework aluminum atoms with the electric field gradient in dehydrated zeolite H,Na-Y has been studied by (27)Al MAS NMR and (27)Al MQMAS NMR spectroscopy at magnetic fields of 9.4 and 17.6 T. Upon adsorption of molecules interacting with bridging OH groups by hydrogen bonds (acetonitrile and acetone), the quadrupole coupling constant of framework aluminum atoms was found to decrease from 16.0 MHz (unloaded zeolite) to 9.4 MHz. Adsorption of molecules, which cause a proton transfer from the zeolite framework to the adsorbates (ammonia and pyridine), reduces the quadrupole coupling constant to 3.8 MHz for coverages of 0.5-2 molecules per bridging OH group. The experiments indicate that the quadrupole coupling constant of framework aluminum atoms in dehydrated zeolite H,Na-Y reflects the chemical state of adsorbate complexes formed at bridging OH groups. In agreement with earlier investigations it was found that a proton affinity of the adsorbate molecules of PA = 812-854 kJ/mol is necessary to induce a proton transfer from the zeolite framework to the adsorbed compounds. This proton transfer is accompanied by a strong improvement of the tetrahedral symmetry of zeolitic framework AlO(4) tetrahedra and a decrease of the electric field gradient. 相似文献
179.
Annapurna Mohanta Dhrubananda Behera 《Physica C: Superconductivity and its Applications》2010,470(4):295-303
Fluctuations on the electrical conductivity of polycrystalline YBa2Cu3O7?δ + xBaZrO3 (x = 1.0, 2.5, 5.0 and 10.0 wt.%) superconductors were investigated from the resistivity vs. temperature data for zero field and 8 T (Tesla) external magnetic fields. Attempts have been made to identify the optimum inclusion of BaZrO3 (BZO) in YBa2Cu3O7?δ (YBCO) superconductors. The phase formation, texture and grain alignments were analyzed by XRD and SEM techniques. Then the effects of superconducting fluctuations on the electrical conductivity of granular composite superconductors were studied for zero field and 8 T external magnetic fields. Though inclusions of BZO sub-micron particles are not expected to influence superconducting order-parameter fluctuation (SCOPF) much, the transition from 2D to 3D of the order parameter in the mean-field region depends on the BZO content in the composites. It has been observed that BZO residing at the grain boundary of YBCO matrix influences the tailing region without having significant change in the mean-field critical temperature. In the present work, attention has been focused mostly in the experimental domain relatively above the Tc. It reveals that, 1 wt.% composite exhibits a better superconducting property in comparison with pure YBCO. 相似文献
180.