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91.
New hybrid organic-inorganic nanocomposites based on functional [Ti16O16(OEt)24(OEMA)8] nano-fillers
Bocchini S Fornasieri G Rozes L Trabelsi S Galy J Zafeiropoulos NE Stamm M Gérard JF Sanchez C 《Chemical communications (Cambridge, England)》2005,(20):2600-2602
New hybrid nanocomposites based on a methacrylate functionalized titanium-oxo cluster as nano-cross-linker show improved mechanical properties, optical transparency and photochromic activity. 相似文献
92.
P. Vigny F. Gaboriau M. Duquesne E. Bisagni D. Averbeck ‡ 《Photochemistry and photobiology》1979,30(5):557-564
Abstract— The newly synthesized linear psoralen derivative 3-carbethoxypsoralen has been shown recently to behave as a monofunctional derivative and has attracted some interest in the psoriasis treatment. In a first attempt to understand, by the fluorescence technique, the molecular mechanism by which it interacts with DNA, a spectroscopic study of the molecule was undertaken. The fluorescence of 3-carbethoxypsoralen at room temperature resembles that of 8-methoxypsoralen with a ten times higher quantum yield. 365 nm irradiation of dilute solutions of 3-carbethoxypsoralen rapidly leads to the formation of two types of highly fluorescent photoproducts. Type 1 photoproducts (λem max = 425 nm, λexc max = 360 nm) have been identified as the result of the addition of a solvent molecule to the 4,5' reaction site of the molecule. Their fluorescence intensity is a hundred times higher for 3-carbethoxypsoralen than for 8-methoxypsoralen. They become negligible when the 4',5' reaction site carries also a carbethoxy group. Type 2 photoproducts exhibit a somewhat different emission (λem max = 443 nm, λexc max = 413 nm). They are probably the result of an opening of the furocoumarin molecule. The implications of the peculiar photochemical properties of 3-carbethoxypsoralen are discussed in view of its biological activity. In addition, the use of fluorescence in monitoring the photobinding of psoralens to DNA is also discussed 相似文献
93.
Jocelyne Giraud-Girard Daniel Maynau 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,23(1):91-98
The equilibrium geometries of Na n F n and Na n F n?1 are optimized forn=2, 3, 4 at the SCF level. The Na n F n molecules appear as formed by Na+ and F? ions. The paper studies the localization of the excess electron in the Na n F n?1 molecules. Na n F n?1 is obtained by removing from Na n F n a fluorine atom, and the excess electron takes the place of this lacking center, and allows a weak bond between the neighbouring Na atoms. Secondary minimum geometries, for which the excess electron has no defined place, are also studied. 相似文献
94.
Grichine A Feofanov A Karmakova T Kazachkina N Pecherskih E Yakubovskaya R Mironov A Egret-Charlier M Vigny P 《Photochemistry and photobiology》2001,73(3):267-277
Molecular in vitro and in vivo properties of 3-devinyl-3-formylchlorin p6 (FCp6) were examined in order to characterize this derivative as a new prospective photosensitizer. The long-wavelength absorption maximum of FCp6 was 690-696 nm (depending on environment). FCp6 was found to bind readily to membranous structures and form complexes with some proteins. The dye was associated with the plasmalemma and distributed rather diffusely along the cytoplasm with ca a three-fold higher accumulation within mitochondria in A549 human adenocarcinoma cells. The spectral analysis revealed that the major part of FCp6 was bound to membranes within cells. The membrane-bound FCp6 was shown to generate singlet oxygen efficiently. The average cytoplasmic concentration of FCp6 in A549 cells achieved ca 80% of its extracellular concentration in complete medium. The dye was characterized by a very fast efflux (16-fold decrease in 2 h). The ex vivo analysis of FCp6 fluorescence in mice revealed that the maximal dye content in blood, tissues, organs and tumor was achieved in less than 1 h after injection, followed by a considerable (ca six-fold) decrease during the next 23 h and a long-term persistence at low level. A preferential accumulation of FCp6 in subcutaneously implanted Ehrlich carcinoma along with its higher retention level comparing to the surrounding skin and muscles were observed in mice treated with different dye doses. In vitro cytotoxic assays with A549 and Raji B-cell lymphoma cells as well as in vivo analyses using Ehrlich carcinoma in mice revealed the very low toxicity of FCp6 without light irradiation and the significant photodynamic activity of this compound. 相似文献
95.
Azaïs T Bonhomme-Coury L Vaissermann J Bertani P Hirschinger J Maquet J Bonhomme C 《Inorganic chemistry》2002,41(4):981-988
We present the structure and a multinuclear solid-state NMR study of a new cyclic aluminophosphinate. The crystallographic structure of [Al(2)(HC(6)H(5)PO(2))(2)(C(4)H(9)OH)(8)]Cl(4) (compound 1) was obtained at low temperature (a = 11.830(7) A, b = 14.216(6) A, c = 17.790(6) A, beta = 91.25(4) degrees, monoclinic, P21/c, Z = 2). (13)C IRCP (inversion recovery cross polarization) and NQS (non quaternary suppression) NMR experiments allowed the complete assignment of the quaternary carbon atom of the phenyl ring and the precise determination of the isotropic /(1)J(P-C)/ coupling constant. (31)P CP MAS dynamics was carefully studied by varying the contact time. Dipolar oscillations even at slow MAS were observed. Up to 11 kHz, these oscillations were more pronounced, and the P-H distance was easily extracted. (27)Al NMR quadrupolar parameters for 1 were obtained with very good accuracy, and unusual satellite transition splitting was observed. Furthermore, the isotropic lines of the inner and outer transitions were clearly observable, leading to the unambiguous determination of the quadrupolar parameters. 相似文献
96.
Florence Babonneau Christian Bonhomme Christel Gervais Jocelyne Maquet 《Journal of Sol-Gel Science and Technology》2004,31(1-3):9-17
The objective of this paper is to discuss the recent advances in high resolution solid state Nuclear Magnetic Resonance (NMR) to characterise sol-gel derived materials. The first part will be focused on methods to describe M i --O--M j connectivities in sol-gel networks. After a brief review on techniques based on scalar J-coupling, we will focus on the use of 17O solid state NMR experiments. Then in a second part, techniques to probe through-space interactions in hybrid networks will be described, with a particular emphasis on the use of high resolution 1H solid state NMR sequences and related two-dimensional homonuclear or heteronuclear correlations. 相似文献
97.
Lidia Andreu Guillo Bénédicte Beylot Paul Vigny Annick Spassky 《Photochemistry and photobiology》1996,64(2):349-355
The present report provides evidence that thymine dimerization can be UVA photosensitized at a tetranucleotide, 5′-TATT-3′, by a 7-methyl-pyrido(3, 4-c)psoralen monoadduct in DNA. The efficiency of the photoprocess depends on the tetranucleotide flanking sequences. These results demonstrate that one DNA lesion can originate the contiguous formation of a second type of lesion and emphasize the sequence-specific response to interaction of drugs with DNA. Results are related to the sensitivity of DNA to 1, 10-phenanthroline-cuprous ion complex nucleolytic activity and discussed in terms of the major role of local deformability of DNA in interaction with ligands. 相似文献
98.
Jocelyne Ethve Philippe Djardin Michel Boissire 《Colloids and surfaces. B, Biointerfaces》2003,28(4):59-293
We present the influence of pH, from pH 4 to 10, with a focus on the neutral range, on the adsorption of lysozyme (isoelectric point pI=11) on a sulphonated membrane and the same membrane pre-treated with poly(ethyleneimine) (PEI). We found a steep increase of the adsorbed amount above pH 6 in phosphate buffer. The adsorbed amount was about twice as low in Tris buffer, around the neutral pH. The difference between the two types of buffer is attributed to their different ionic composition. High interfacial concentration in phosphate buffer is especially linked to the phosphate divalent anions. In the presence of divalent sulphate anions, we measured the same level of interfacial concentration than with phosphate buffer. With the PEI pre-treated membrane, we observed, on the time scale of our experiments (15–20 h), similar adsorbed amounts than on the raw membrane, showing that the PEI layer does not constitute a true barrier to the penetration of lysozyme into the membrane core. However, its presence leads to a slower adsorption rate in a system where convection does not occur through the membrane. 相似文献
99.
D. Averbeck ‡ E. Bisagni ‡ J. P. Marquet § P. Vigny | F. Gaboriau | 《Photochemistry and photobiology》1979,30(5):547-555
Abstract— Derivatives of psoralen substituted at the position 3 and/or 5' with various substituents (CN, CO-R or COO-R) have been newly synthesized. Their photobiological reactivity was determined by measuring the effects on survival and the induction of cytoplasmic 'petite' mutations (rho-) in the haploid yeast Saccharomyces cereuisiae after treatment with 365-nm irradiation in the presence of the different compounds. The effects were compared to those of known mono-functional compounds such as angelicin, 3-carbethoxypsoralen and 5,7-dimethoxycoumarin and bi-functional compounds such as psoralen and 8-methoxypsoralen for which the photoaffinity to DNA is well known. The derivative carrying a CN group in position 3 of the psoralen molecule exhibited effects comparable to those of the bi-functional agent 8-methoxypsoralen. Three derivatives substituted at position 3 showed a biological activity comparable to those of the mono-functional agent 3-carbethoxypsoralen. Two compounds substituted at position 5' by COOH or COOCH3 -groups were much less photobiologically active than the corresponding derivatives substituted in position 3. This suggested that the furanic site of the psoralen molecule may be photobiologically more active than the 3,4 site. Four newly synthesized angular derivatives, i.e. furo (2,3 f, g) coumarins, were found to be two to three times less active than angelicin.
At the dose rate of 365-nm irradiation used the measure of survival and rho- induction per viable cell allowed the classification of some of the compounds as mono- and some as bi-functional agents in analogy to known mono- and bi-functional compounds. 相似文献
At the dose rate of 365-nm irradiation used the measure of survival and rho
100.
Irshad Mohammad Lucie Blondeau Jocelyne Leroy Hicham Khodja Magali Gauthier 《Molecules (Basel, Switzerland)》2021,26(18)
Achieving the full potential of magnesium-ion batteries (MIBs) is still a challenge due to the lack of adequate electrodes or electrolytes. Grignard-based electrolytes show excellent Mg plating/stripping, but their incompatibility with oxide cathodes restricts their use. Conventional electrolytes like bis(trifluoromethanesulfonyl)imide ((Mg(TFSI)2) solutions are incompatible with Mg metal, which hinders their application in high-energy Mg batteries. In this regard, alloys can be game changers. The insertion/extraction of Mg2+ in alloys is possible in conventional electrolytes, suggesting the absence of a passivation layer or the formation of a conductive surface layer. Yet, the role and influence of this layer on the alloys performance have been studied only scarcely. To evaluate the reactivity of alloys, we studied InSb as a model material. Ex situ X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy were used to investigate the surface behavior of InSb in both Grignard and conventional Mg(TFSI)2/DME electrolytes. For the Grignard electrolyte, we discovered an intrinsic instability of both solvent and salt against InSb. XPS showed the formation of a thick surface layer consisting of hydrocarbon species and degradation products from the solvent (THF) and salt (C2H5MgCl−(C2H5)2AlCl). On the contrary, this study highlighted the stability of InSb in Mg(TFSI)2 electrolyte. 相似文献