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101.
Vitalij A. Chatyrko Elzbieta Pol 《Proceedings of the American Mathematical Society》2000,128(4):1207-1213
In this note we construct a family of continuum many hereditarily strongly infinite-dimensional Cantor manifolds such that for every two spaces from this family, no open subset of one is embeddable into the other.
102.
Marek Pyda Elzbieta Nowak‐Pyda Jimmy Mays Bernhard Wunderlich 《Journal of Polymer Science.Polymer Physics》2004,42(23):4401-4411
The low‐temperature heat capacity of poly(butylene terephthalate) (PBT) was measured from 5 to 330 K. The experimental heat capacity of solid PBT, below the glass transition, was linked to its approximate group and skeletal vibrational spectrum. The 21 skeletal vibrations were estimated with a general Tarasov equation with the parameters Θ1 = 530 K and Θ2 = Θ3 = 55 K. The calculated and experimental heat capacities of solid PBT agreed within better than ±3% between 5 and 200 K. The newly calculated vibrational heat capacity of the solid from this study and the liquid heat capacity from the ATHAS Data Bank were applied as reference values for a quantitative thermal analysis of the apparent heat capacity of semicrystalline PBT between the glass and melting transitions as obtained by differential scanning calorimetry. From these results, the integral thermodynamic functions (enthalpy, entropy, and Gibbs function) of crystalline and amorphous PBT were calculated. Finally, the changes in the crystallinity with the temperature were analyzed. With the crystallinity, a baseline was constructed that separated the thermodynamic heat capacity from cold crystallization, reorganization, annealing, and melting effects contained in the apparent heat capacity. For semicrystalline PBT samples, the mobile‐amorphous and rigid‐amorphous fractions were estimated to complete the thermal analysis. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4401–4411, 2004 相似文献
103.
104.
Zygmunt Bak 《Czechoslovak Journal of Physics》2003,53(1):5-9
We consider interlayer magnetic coupling in a superlattice and/or overlayer in the case when spacer layer has the tendency towards formation of the helical spin density wave. Within phenomenological Landau-Ginzburg approach we show that the mutual interplay of the SDW and interlayer coupling spin polarization can lead to the helical interlayer coupling. When surface anisotropy is accounted for the effective interaction mimics interlayer biquadratic coupling. 相似文献
105.
106.
Eunhee Hwang Sae Mi Lee Sora Bak Hee Min Hwang Hyunjung Kim Hyoyoung Lee 《Tetrahedron letters》2018,59(44):3969-3973
The first methodology of CH arylation of heteroarene via 2D transition metal dichalcogenides that have catalytically active edge functional groups was described. The terminal sulfur groups could effectively catalyze a formation of an azo-linked intermediate with aryl diazonium salts, leading to produce heteroarenes with good yields. This novel methodology using bulk 2D transition metal dichalcogenides that have catalytically active edge functional groups can apply for various reactions to achieve CC bond formation in the fields of heterogeneous catalysis that is easily separable, highly reusable, and inexpensive method. 相似文献
107.
Agnieszka Lacz Barbara Bak Radoslaw Lach 《Journal of Thermal Analysis and Calorimetry》2018,133(1):107-114
Nb-doped BaWO4 with the assumed formula BaW1?xNbxO4?δ (x = 0, 0.005, 0.01, 0.02 and 0.05) were prepared by solid-state reaction method. Crystal structure and phase composition were determined by X-ray diffraction method. Scanning electron microscopy (SEM) coupled with energy-dispersive spectrometry (EDS) was used to describe microstructure and chemical composition of synthesised materials. It was found that solubility limit of niobium in the BaWO4 structure is the range 0.5–1 mol%, as formation of second phase—Ba5Nb4O15—was observed for samples with higher dopant content. For evaluation of the chemical stability of synthesized materials, the comparative CO2/H2O exposure test was performed. Samples were exposed to carbon dioxide- and water vapour-rich atmosphere (7% CO2 in air, 100% RH) at 298 K for 700 h. During this exposition, the chemical reactions between the samples and the surrounding gaseous atmosphere resulting in formation of barium hydroxide and/or barium carbonate can process. Thermogravimetry (TG) method was used for chemical stability evaluation. The comparison of samples before and after the CO2/H2O exposure test was performed. To support the interpretation of TG results, the analysis of gaseous products evolved during thermal treatment of the samples was done using mass spectrometer. The effect of dopant on the BaWO4 chemical stability improvement was observed. In order to determine the electrical properties of obtained materials, the DC resistance measurements in synthetic air atmosphere were taken. It was shown that niobium doping and the presence of second phase—Ba5Nb4O15—leads to an increase in the total conductivity of synthesised materials. 相似文献
108.
109.
110.
Wojciech Duczmal Elzbieta Śliwińska Beata Maciejewska Bogdan Marciniec Hieronim Maciejewski 《Transition Metal Chemistry》1995,20(5):435-439
Summary Trisubstituted silanes, HSiR3-n
X
n
(R = Me or Et, X = Cl, OEt, or Ph; n = 0–3) oxidatively add to the complex [RhCl(cod)(1-hexene)] (cod = cycloocta-1,5-diene) to yield [RhCl(cod)(1-hexene)(H)(SiR3)] [(1)]. Subsequent steps of hydrosilylation follow, i.e. cis-insertion of the alkene (- rearrangement) and then reductive elimination of the product, according to the general Chalk and Harrod scheme. A quantitative correlation between the second order rate constant, k
1, of the oxidative addition (followed spectrophotometrically) at 20°C in benzene solution and the structure of the trisubstituted silane represented by Stereoelectronic parameters , and E' for the SiR3-n
X
n
groups was established. The maximal hydrosilylation rate followed by g.l.c., is strongly retarded by highly electronegative substituents X on silicon and results from the elimination rate of the hydrosilylation product from (1) and the maximal concentration of (1) in solution.Dedicated to Professor K. Rühlmann on the occasion of his 65th birthday. Part XXVII in the series Catalysis of Hydrosilylation; for Part XXVI see Polish J. Appl. Chem., 38, 169 (1994). 相似文献