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921.
C.E.?EkumaEmail author V.I.?Anisimov J.?Moreno M.?Jarrell 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(1):23
We report the electronic structure of monoclinic CuO as obtained from first principles calculations utilizing density functional theory plus effective Coulomb interaction (DFT + U) method. In contrast to standard DFT calculations taking into account electronic correlations in DFT + U gave antiferromagnetic insulator with energy gap and magnetic moment values in good agreement with experimental data. The electronic states around the Fermi level are formed by partially filled Cu 3d x²?y² orbitals with significant admixture of O 2p states. Theoretical spectra are calculated using DFT + U electronic structure method and their comparison with experimental photoemission and optical spectra show very good agreement. 相似文献
922.
E. Moreno F.J. Girón M.L. Martínez F.J. Vázquez-Polo M.A. Negrín 《European Journal of Operational Research》2013
In the presence of covariates, the cost-effectiveness analysis of medical treatments shows that the optimal treatment varies across the patient population subgroups, and hence to accurately define the subgroups is a crucial step in the analysis. A patient subgroup definition using only influential covariates within the potential set of patients covariates established by the expert has recently been proposed, and the influential covariates were chosen from the univariate distributions of the effectiveness and the cost, conditional on the effectiveness. In this paper, we argue that the Bayesian variable selection procedure should be developed using the bivariate distribution of the cost and the effectiveness, which is not the usual practice. This new approach, provides results with wider applicability and more understandable without a significative increase in the complexity of the procedure. For real and simulated data sets, optimal treatments for subgroups are found, and compared with that from previous methods. 相似文献
923.
A. Ipatov L. Moreno N. Abramova A. Bratov Yu. Vlasov K. Dominges 《Russian Journal of Applied Chemistry》2009,82(8):1384-1389
Results obtained with an “electronic tongue” device based on an array of ion-selective field transistors integrated into a
flow-injection system are presented. The component concentrations in mineral waters from Spanish manufacturers are analyzed.
Processing of analytical signals by the partial least squares method improves the accuracy of component determination in mineral
waters of close compositions. A single chip integrates sensors sensitive to pH, K+, Na+, Ca2+, and Cl− ions. Mineral waters are classified and the concentrations of the main components are calculated with an error not exceeding
10%. 相似文献
924.
M. Victoria Gómez Andrés Moreno Abel de Cózar Antonio de la Hoz Pilar Prieto 《Tetrahedron》2009,65(27):5328-4001
Diels-Alder cycloaddition of 3-nitro-1-(p-toluenesulfonyl)indole 1 with dienes 2-6 under microwave irradiation in solvent-free conditions gave carbazole derivatives after elimination of the nitro group and in situ aromatization. While 3-nitro-1-(p-toluenesulfonyl)pyrrole 11 afforded indole derivatives, 4-nitro-1-(p-toluenesulfonyl)pyrazole 13 with cyclohexadiene 2 did not afford the expected cycloadduct but instead gave 1-cyclohexen-2-ylpyrazole 16. This process occurred by hydrolysis of the 1-(p-toluenesulfonyl) group, protonation of the diene and nucleophilic addition of the pyrazolate ion, as elucidated by computational studies. Reaction of nitroindole 1 with cyclohexadiene 2 afforded exclusively the endo stereoisomer (10endo) in a tandem hetero Diels-Alder/[3,3] sigmatropic shift, as determined by computational calculations. 相似文献
925.
Rocha BA Moreno FB Delatorre P Souza EP Marinho ES Benevides RG Rustiguel JK Souza LA Nagano CS Debray H Sampaio AH de Azevedo WF Cavada BS 《Applied biochemistry and biotechnology》2009,152(3):383-393
The unique carbohydrate-binding property of lectins makes them invaluable tools in biomedical research. Here, we report the purification, partial primary structure, carbohydrate affinity characterization, crystallization, and preliminary X-ray diffraction analysis of a lactose-specific lectin from Cymbosema roseum seeds (CRLII). Isolation and purification of CRLII was performed by a single step using a Sepharose-4B-lactose affinity chromatography column. The carbohydrate affinity characterization was carried using assays for hemagglutination activity and inhibition. CRLII showed hemagglutinating activity toward rabbit erythrocytes. O-glycoproteins from mucine mucopolysaccharides showed the most potent inhibition capacity at a minimum concentration of 1.2 microg mL(-1). Protein sequencing by mass spectrometry was obtained by the digestion of CRLII with trypsin, Glu-C, and AspN. CRLII partial protein sequence exhibits 46% similarity with the ConA-like alpha chain precursor. Suitable protein crystals were obtained with the hanging-drop vapor-diffusion method with 8% ethylene glycol, 0.1 M Tris-HCl pH 8.5, and 11% PEG 8,000. The monoclinic crystals belong to space group P2(1) with unit cell parameters a = 49.4, b = 89.6, and c = 100.8 A. 相似文献
926.
927.
Marta Corzo-Martínez Rosa Lebrón-Aguilar Mar Villamiel Jesús Eduardo Quintanilla-López F. Javier Moreno 《Journal of chromatography. A》2009,1216(43):7205-7212
This article describes a comprehensive characterization of bovine β-lactoglobulin peptides glycated with an aldohexose (galactose) or a ketohexose (tagatose), derived from in vitro gastrointestinal digestion, by liquid chromatography coupled to positive electrospray ion trap tandem mass spectrometry. In addition to the dissociation pathway previously described for aldohexoses-derived Amadori compounds, i.e. formation of the pyrylium ([M+H]+-54) and furylium ions ([M+H]+-84) via the oxonium ion ([M+H]+-18), another and more direct fragmentation route involving the formation of the imminium ion ([M+H]+-150) is also reported following extensive glycation rates of β-lactoglobulin with both carbohydrates. These results indicated that the analysis of digested proteins by LC-ESI-MS2 on a three-dimensional ion trap monitoring neutral losses is an efficient and direct method to identify peptides glycated not only through the Amadori rearrangement but also via the Heyns rearrangement. Nevertheless, as the predominating MS2 fragmentation pattern of the glycated peptides is derived from the sugar moiety, the sequence-informative b- and y-ions resulting from peptide backbone cleavage were undetected. To overcome this drawback, and taking advantage of multi-stage fragmentation capabilities of ion traps, the indicative Amadori and Heyns-derived imminium ions were successfully used in MS3 analyses to identify the peptide backbone, as well as the specific glycation site. In addition, further MS4 analyses were needed to carry out the characterization of doubly glycated peptides. 相似文献
928.
José Luis Pérez Pavón Ana María Casas FerreiraMaría Esther Fernández Laespada Bernardo Moreno Cordero 《Journal of chromatography. A》2009,1216(39):6728-6734
The aim of the present work is to propose a method for the determination of ibuprofen, as a typical representative of pharmaceutical compounds, in aqueous samples. To do so, an in situ derivatization reaction in aqueous medium was employed in the vial of a headspace sampler (HS), after which instrumental measurements were made with gas chromatography-mass spectrometry (GC-MS). As the injection system we propose a programmed temperature vaporizer (PTV) where, in solvent vent mode, better results can be obtained than with the conventional split and splitless injection modes. Since the derivatization reaction takes place in the HS vial, after the mixing of reagents and the sealing of the vial, the whole process takes place on-line, with no need for intermediate steps. The simplicity and speed of the method – analysis throughput: 10.5 min – together with the limit of detection obtained (0.23 μg/L), bearing in mind that no preconcentration step or later clean-up step are required, make this a good method for the analysis of ibuprofen in aqueous samples of urban waste water. 相似文献
929.
Manuel A.V. Ribeiro da Silva Ana I.M.C. Lobo Ferreira Ana Rita G. Moreno 《The Journal of chemical thermodynamics》2009,41(1):109-114
The standard (p° = 0.1 MPa) molar enthalpies of formation of 2-, 3-, and 4-chloronitrobenzene isomers, in the crystalline state, at T = 298.15 K, were derived from the standard (p° = 0.1 MPa) massic energies of combustion, in oxygen, at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of sublimation of the isomers, at T = 298.15 K, were obtained by high temperature Calvet microcalorimetry.
Empty Cell | /(kJ · mol?1) | /(kJ · mol?1) | /(kJ · mol?1) |
---|---|---|---|
2-Chloronitrobenzene | 2939.5 ± 0.7 | 18.7 ± 1.0 | 80.9 ± 1.5 |
3-Chloronitrobenzene | 2915.8 ± 0.8 | 42.4 ± 1.2 | 82.5 ± 1.5 |
4-Chloronitrobenzene | 2921.7 ± 1.4 | 36.5 ± 1.6 | 76.2 ± 2.1 |