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1.
Ricardo de Souza Pereira Nivaldo AntÔnio Parizotto Vitor Baranauskas 《Applied biochemistry and biotechnology》1996,59(2):135-143
Different strains of baker’s yeast(Saccharomyces cerevisiae) were imaged with an atomic force microscope (AFM). The images of uncoated and nonfixed samples were reproducible with high-constrast
and nanometer-resolution. Molecules from the polysaccharide surface of the cell wall were pictured and the distance of atoms
was measured. The preparation of samples was easy, suggesting that AFM is a useful tool in this type of analyses. 相似文献
2.
The new Pd(II), Pt(II), Re(V), Mo(VI) and W(VI) complexes of 2-hydroxynicotinic acid (H2nicO), trans-[PdCl(HnicO)(PPh3)2]·0.75CH3CN (1), K[PdCl(HnicO)2]·H2O (2), [Pd(HnicO)2(bipy)] (3), cis-[PtCl(HnicO)(PPh3)2]·0.75CH3OH·0.5H2O (4), [PtCl(HnicO)(bipy)] (5), cis-[ReOI2(HnicO)(PPh3)] (6), Na2[Mo2O6(HnicO)2]·5H2O (7), Na2[Mo4O12(HnicO)2]·2H2O (8) and Na2[W2O6(HnicO)2]·5H2O (9) have been prepared. The crystal structures of 1 and 4, were determined by X-ray diffraction and show the HnicO− ligand coordinated to palladium or platinum through the nitrogen atom only. Infrared, Raman, 1H and 13C{1H} NMR spectroscopic data for the complexes are presented and are in agreement with the crystallographic results. 相似文献
3.
Julliane Diniz Yoneda Magaly Giro Albuquerque Ktia Zaccur Leal Peter R. Seidl Ralph A. Wheeler Scott E. Boesch Ricardo Bicca de Alencastro Maria Cecília B.V. de Souza Vitor F. Ferreira 《Journal of Molecular Structure》2006,778(1-3):97-103
Conformational analysis of nucleosides may have direct applications to the structure–activity relationship (SAR) studies and in the design of new drug candidates. Although conformational analysis may be accessed in many different ways, in this work it was performed using molecular dynamics (MD) simulation in order to study the dynamic behavior of a nucleoside derivative of 1,4-dihydro-4-oxoquinoline-3-carboxylic acid, synthesized by our group as a potential antiviral agent. The MD simulation was carried out during 10 ns in vacuum and in a box of water at two different temperatures (i.e., 300 and 600 K) using the AMBER force field. The in vacuum MD simulation results are in agreement with the crystallographic structure and with the DFT calculations of the nucleoside, revealing the anti conformer as the more stable one. The simulation in water, however, shows that both conformers may exist at 300 K, the temperature of the in vivo and in vitro assays, revealing that both the syn and anti conformers should be considered in a MD simulation study of the inhibitor–enzyme complex. Simulations are also in agreement with the NOE experiment, which shows that the anti conformer is the preferential one in DMSO-d6 solution at 298 K. 相似文献
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Vitor Matos Julio D. Silva Dan Marchesin 《Bulletin of the Brazilian Mathematical Society》2016,47(2):545-559
Themain goal of ourwork is to showthat there exists a class of 2×2 Riemann problems for which the solution comprises a singlewave group for an open set of initial conditions. This wave group comprises a 1-rarefaction joined to a 2-rarefaction, not by an intermediate state, but by a doubly characteristic shock, 1-left and 2-right characteristic. In order to ensure that perturbations of initial conditions do not destroy the adjacency of the waves, local transversality between a composite curve foliation and a rarefaction curve foliation is necessary. 相似文献
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As part of an ongoing program directed toward the preparation of antraciclinones1 and aryl substituted lapachones2, which are important anticancer and antibiotic3 agents, we became interested in a efficient synthesis of substituted 1,4-naphthoquinones, such as juglone (3). This compound has received some attention due its activity as an allelophatic compound4. An extensive analysis of the literature procedures indicated that several methods are available starting from 1,5-dihydroxynaphthalene (1). All the procedures explored the oxidation of carbon four of the naphthyl ring by several known reagents, such as, chromium trioxide-piridine5, thallium trinitrate5, chromic acid6, peracetic acid7, dichromate8, iron (III) chloride9 and mercuric oxide10. None of the several known methods for the preparation of (3) proceeded in satisfactory yield (except for the thallium trinitrate method which gave 642 yield) and most of them gave a mixture of 1,2 and 1,4-naphthoquinone. 相似文献
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