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71.
The reliability of 1.5 ?m InGaAsP/InP DC-PBH lasers prepared by two-step hydride VPE and LPE was estimated at the 70°C, 5 mW constant-power mode. The low degradation rate (8×10?5/h) indicated high reliability of the two-step VPE-LPE-grown LDs with the VPE-grown active layer. 相似文献
72.
We prove the Kato conjecture for square roots of elliptic second order non-self-adjoint operators in divergence formL = -div(A∇) on strongly Lipschitz domains in ℝn, n≥2, subject to Dirichlet or to Neumann boundary conditions. The method relies on a transference procedure from the recent
positive result on ℝn in [2]. 相似文献
73.
Y. Nishimoto 《Journal of Thermal Analysis and Calorimetry》1993,40(2):413-418
The effect of oxygen concentration on the melting of this eutectic was investigated by DSC. In the deoxygenized solution, an endothermic peak attributed to the eutectic transition was observed in the course of heating, and its peak temperature is around ?21.5°C. Another endothermic peak appeared at lower temperature in the presence of oxygen. As the oxygen content in the solution increases, the temperature of this peak is shifted to lower temperature. The transition at the lower temperature are associated with the melting of eutectic carrying oxygen. The same results are given in the NMR data. 相似文献
74.
75.
Shunsuke Nishimoto Stefanus Harjo Takashi Kamiyama Michihiro Miyake 《Journal of solid state chemistry》2006,179(6):1892-1897
A deuterated n=1 Ruddlesden-Popper compound, DLnTiO4 (HLnTiO4, Ln=La, Nd and Y), was prepared by an ion-exchange reaction of Na+ ions in NaLnTiO4 with D+ ions, and its structure was analyzed by Rietveld method using powder neutron diffraction data. The structure analyses showed that DLaTiO4 and DNdTiO4 crystallized in the space group P4/nmm with a=3.7232(1) and c=12.3088(1) Å, and a=3.7039(1) and c=12.0883(1) Å, respectively. On the other hand, DYTiO4 crystallized in the space group P21/c with a=11.460(1), b=5.2920(4), c=5.3628(5) Å and β=90.441(9)°. The loaded protons were found to statistically occupy the sites around an apical oxygen of TiO6 octahedron in the interlayer of these compounds, rather than Na atom sites in NaLnTiO4. 相似文献
76.
Yamada Ji Satoki S Mishima S Akashi N Takahashi K Masuda N Nishimoto Y Takasaki S Anzai H 《The Journal of organic chemistry》1996,61(12):3987-3995
Efficient synthetic methods for the construction of a wide variety of unsymmetrical tetrathiafulvalenes (TTFs) via the Me(3)Al-promoted reactions of organotin thiolates or selenolates with esters are described. Reaction of tin thiolates (3a-c and 10) and selenolates (3d, 5, and 7) with esters (11a,b) in the presence of Me(3)Al as a Lewis acid gave dihydrotetrathiafulvalene derivatives (12, 14, 15, and 17-20) and 1,3-dithiane derivatives (13 and 16). In addition, the synthesis of diselenadithiafulvalene derivatives (25-28) could be accomplished by Me(3)Al-mediated reaction of tin thiolate (2a) or selenolates (3d and 5) with esters (22a, 22d, and 24). Furthermore, the application of the Me(3)Al-promoted reaction of tin thiolate (34) with esters (11a-b, 22a-d, and 35a-b) for the synthesis of unsymmetrical TTFs-fused donors enabled us to obtain various TTFs-fused systems (29-33) in short steps. 相似文献
77.
A new parameterization for the first transition metal has been proposed in the framework of CNDO /2 method. We carried out CNDO /2 calculation of hexamine complexes [M(NH3)6]2+ and hexa-aquo complexes [M(OH2)6]2+ in the high spin state where M = Mn, Fe, Co, Ni, and Cu, using new parameters. It is shown that the calculated order of binding energy is Mn? L < Fe? L < Co? L < Ni? L ≈ Cu? L (where L means the ligand), and is in good agreement with experiment. We discussed how the orbital nodes affect the nature of bonding between metal and ligand. 相似文献
78.
The SCFMO method in the variable approximation has been extended to heteroatomic systems. The transition energies and bond lengths of a group of nitrogen- and oxygen-containing molecules have been calculated and the singlet transition energies are in good agreement with experiment.
Supported by the U. S. Atomic Energy Commission and National Science Foundation. 相似文献
Zusammenfassung Die SCF MO Methode in der Näherung der variablen wurde auf Systeme mit Heteroatomen ausgedehnt. Die Übergangsenergien und Bindungslängen einer Gruppe von Molekülen mit Stickstoff- und Sauerstoffatomen wurden berechnet. Die Singulettübergaugsenergien befinden sich in guter Übereinstimmung mit dem Experiment.
Résumé Nous avons étendu la méthode SCF MO dans l'approximation des variables aux systèmes hétéroatomiques et calculé les énergies de transition et les longueurs de liaison d'un groupe de molécules avec nitrogène et oxygène. Les énergies des transitions singulets s'accordent bien à l'expérience.
Supported by the U. S. Atomic Energy Commission and National Science Foundation. 相似文献
79.
In order to obtain a relationship between the molecular dimension and the correlation effect, RPA method has been applied to the calculation of electronic transition energies of linear polyenes. It has been found that the effect of electron correlation on the excitation energy decreases with increasing the size of molecule. The calculated oscillator strengths are remarkably improved by RPA calculation. 相似文献
80.
Photophysical characteristics of N-substituted C5-C5'-linked dihydrothymine dimers (1a,b[meso], meso compounds of [5R,5'S]-bi-5,6-dihydrothymines; 1a,b[rac], racemic compounds of [5R,5'R]-bi-5,6-dihydrothymines and [5S,5'S]-bi-5,6-dihydrothymines) in aqueous solution with varying contents of less-polar aprotic solvent such as tetrahydrofuran or dioxane have been investigated by UV-absorption, and steady-state and time-resolved fluorescence spectroscopies. Among the C5-C5'-linked dimers, (5R,5'S)-bi-5,6-dihydro-1-methylthymine (1a[meso]) showed a red-shifted weak UV-absorption band at 270-350 nm and excimer fluorescence emission at lambda max = 370 nm with a quantum yield (phi F) of approximately 0.1 in phosphate buffer (pH < 10) at 293 K. Racemic compound of 5,6-dihydro-1-methylthymine dimer (1a[rac]), meso and racemic compounds of 5,6-dihydro-1,3-dimethylthymine dimers (1b[meso] and 1b[rac]) in phosphate buffer were nonfluorescent under similar conditions. The UV-absorption and fluorescence spectral characteristics of 1a[meso] in aqueous solution were interpreted in terms of intramolecular stacking interactions between the dihydropyrimidine chromophores leading to a preferential "closed-shell" conformation both in the ground state and the excited singlet state. In basic solutions at pH > pKa = 11.7, the fluorescence quantum yield of 1a[meso] decreased due to a dominant "open-shell" conformation resulting from the electrostatic repulsion between the deprotonated dihydrothymine chromophores of 1a[meso] in a dianion form. 相似文献