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691.
Thez-pinch equilibrium with non zero azimuthal current was calculated for power dependences in this paper. The pressure equilibrium curves have no maximum in thez-pinch centre and look more like a gass-puff pressure curves. The total current density is formed by gradB drift current density, curvature drift current density and magnetization current density in this case.This research has been conducted as part of the research project Magnetic Pinches Stable Structure Study and have been supported by GACR grant No. 202-95-0178. 相似文献
692.
693.
694.
P. J. Urban 《Fresenius' Journal of Analytical Chemistry》1961,179(6):415-422
Summary The colorimetric method of Sörbo for the determination of thiosulphate has been improved in such a way that polythionates do not interfere; it has also been modified for use with larger volumes of solution. The procedure depends on the production of thiocyanate equivalent to the thiosulphate, and determination of the thiocyanate with an excess of ferric iron. By careful control of the pH using an acetate buffer, the cyanolysis of polythionates and hence their interference is avoided. 相似文献
695.
The correlation energies obtained by the fourth-order diagrammatic perturbation theory were analyzed for three diatomic molecules: N2, CO, and F2. The results were compared with correlation energies obtained previously for the ten-electron hydrides HF, H2O, and NH3. The relative importance of contributions which arise from the double excitations, from the quadruple excitations, as well as from the renormalization term was investigated. It is shown that for the diatomic molecules under study these contributions are considerably larger than for the ten-electron hydrides not only in absolute value but also in percentage: they represent about 3, 3, and 5%, respectively, of the valence shell correlation energy obtained by the perturbation theory up to the fourth order. A careful analysis of the fourth-order correlation effects is also presented for the reaction energy of the process ½H2 + ½F2 = HF. 相似文献
696.
Günter Urban Karlheinz Sünkel Wolfgang Beck 《Journal of organometallic chemistry》1985,290(3):329-339
The compounds (π-C5H5)(CO)2LM-X (L = CO, PR3; M = Mo, W; X = BF4, PF6, AsF6, SbF6) react with H2S, p-MeC6H4SH, Ph2S and Ph2SO(L′) to give ionic complexes [(π-C5H5)(CO)2LML′]+ X−. Also sulfur-bridged complexes, [(π-C5H5)(CO)3W---SH---W(CO)3(π-C5H5)]+ AsF6− and [(π-C5H5)(CO)3M-μ-S2C=NCH2Ph-M(CO)3(π-C5H5)], have been obtained. Reactions with SO2 and CS2 have been examined. 相似文献
697.
The separation of three common anabolic steroids (methyltestosterone, methandrostenolone and testosterone) was performed for the first time by capillary EKC. Different charged CD derivatives and bile salts were tested as dispersed phases in order to achieve the separation. A mixture of 10 mmol/L succinylated-beta-CD with 1 mmol/L beta-CD in a 50 mmol/L borate buffer (pH 9) enabled the separation of the three anabolic steroids in less than 9 min. Concentration LODs, obtained for these compounds with low absorption of UV light, were approximately 5 x 10(-5) mol/L. The use of online reverse migrating sample stacking with large-volume injection (the effective length of the capillary) enabled to improve the detection sensitivity. Sensitivity enhancement factors (SEFs) ranging from 95 (for testosterone) to 149 (for methyltestosterone) were achieved by single stacking preconcentration. Then, the possibilities of multistep stacking to improve the sensitivity for these analytes were investigated. SEFs obtained by double stacking preconcentration ranged from 138 to 185, enabling concentration LODs of 2.79 x 10(-7) mol/L (for methyltestosterone), 3.47 x 10(-7) mol/L (for testosterone) and 3.56 x 10(-7) mol/L (for methandrostenolone). Although online triple stacking preconcentration was achieved, its repeatability was very poor and SEFs for the studied analytes were not calculated. 相似文献
698.
The netropsin molecule preferentially binds to the four consecutive A.T base pairs of the DNA minor groove and could therefore inhibit the expression of specific genes. The understanding of its binding on a molecular level is indispensable for computer-aided design of new antitumor agents. This knowledge could be obtained via molecular dynamics (MD) and docking simulations, but in this case appropriate force field parameters for the netropsin molecule should be explicitly defined. Our parametrization was based on the results of quantum chemical calculations. The resulting set of parameters was able to reproduce bond lengths, bond angles, torsional angles of the ab initio minimized geometry within 0.03 A, 3 deg and 5 deg, respectively, and its vibrational frequencies with a relative error of 4.3% for low and 2.8% for high energy modes. To show the accuracy of the developed parameters we calculated an IR spectrum of the netropsin molecule using MD simulation and found it to be in good agreement with the experimental one. Finally, we performed a 10 ns long MD simulation of the netropsin-DNA complex immersed in explicit water. The overall complex conformation remained stable at all times, and its secondary structure was well retained. 相似文献
699.
Pulses from a mechanically chopped CO-laser were used to optically pump the first vibrational level of NO molecules in their fundamental band near 5.3 μm. The population of NO (υ = 1) was followed by measuring the resonance fluorescence of NO-γ-bands from a microwave discharge lamp in the UV region. Analysis of the first order decays of NO(υ = 1) following the excitation pulses yielded rate constants for V---T and V---V energy transfer processes in collisions of NO(υ = 1) with ground state NO and added gas molecules He, Ne, Ar, Kr, Xe, H2, HD, D2, N2, O2 and N2O. 相似文献
700.
Synthese und Konfigurationszuordnung eines potentiell antimikrobiellen 5,6-Dihydroxyisobenzofuranons
Summary Isobenzofuranone3 was prepared by KMnO4-oxidation of2. 3 was reacted to give acetals4–10, which adopt the boat-conformation.3 and its acylated derivatives11–13 on the other hand prefer the chair-conformation. The relative configurations of3–13 at the chiral centres 3a, 5, 6, and 7a were determined by1H-NMR-spectroscopy. 相似文献