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101.
Comparison of the efficiency and the specificity of DNA-bound and free cationic porphyrin in photodynamic virus inactivation 总被引:1,自引:1,他引:0
Zupán K Egyeki M Tóth K Fekete A Herényi L Módos K Csík G 《Journal of photochemistry and photobiology. B, Biology》2008,90(2):105-112
The risk of transmitting infections by blood transfusion has been substantially reduced. However, alternative methods for inactivation of pathogens in blood and its components are needed. Application of photoactivated cationic porphyrins can offer an approach to remove non-enveloped viruses from aqueous media. Here we tested the virus inactivation capability of meso-Tetrakis(4-N-methylpyridyl)porphyrin (TMPyP) and meso-Tri-(4-N-methylpyridyl)monophenylporphyrin (TMPyMPP) in the dark and upon irradiation. T7 bacteriophage, as a surrogate on non-enveloped viruses was selected as a test system. TMPyP and TMPyMPP reduce the viability of T7 phage already in the dark, which can be explained by their selective binding to nucleic acid. Both compounds proved to be efficient photosensitizers of virus inactivation. The binding of porphyrin to phage DNA was not a prerequisite of phage photosensitization, moreover, photoinactivation was more efficiently induced by free than by DNA bound porphyrin. As optical melting studies and agarose gel electrophoresis of T7 nucleoprotein revealed, photoreactions of TMPyP and TMPyMPP affect the structural integrity of DNA and also of viral proteins, despite their selective DNA binding. 相似文献
102.
The acceptance of a tablet batch is based both on the content uniformity test and on the assay. It is shown that these two characteristics are not independent, and the acceptance criteria for them are not even consistent. For content uniformity range three methods of calculation are compared: the present European Pharmacopoeia method, a tolerance range method with improved k tolerance factor and a one-way random effects analysis of variance model. To resolve the inconsistency several options are discussed: applying the holistic content uniformity range alone; using content uniformity standard deviation and assay mean simultaneously or applying a criterion based on Taguchi's quadratic loss function. 相似文献
103.
Kéki S Nagy L Török J Tóth K Lévai A Zsuga M 《Rapid communications in mass spectrometry : RCM》2007,21(11):1799-1808
The pathways of the ([M+H](+)) ions generated from electrosprayed solutions of nine 1,3,5-trisubstituted 2-pyrazoline derivatives were studied using energy-variable collision-induced dissociation (CID) and pseudo-MS(3) (in-source CID combined with MS/MS) methods. It was shown that under CID conditions several structurally important product ions such as the 2,4-substituted azete and 1,2-substituted aziridine ions were formed. The compositions of the product ions were unambiguously supported by accurate mass measurement (mass accuracy was within +/- 8 ppm). The fragmentation pathways of 1,3,5-trisubstituted 2-pyrazolines were established by means of pseudo-MS(3). It was found that a substituent at the N-1 position greatly affects the fragmentation pathways of the 2-pyrazoline derivatives. The 1-acetyl- and 1-propionyl-2-pyrazoline derivatives dissociate mainly through formation of a pyrazolium cation, while in the case of 1-phenyl-2-pyrazoline derivatives product ions arising from the consecutive fragmentation of 2,4-substituted azete and 1,2-substituted aziridine ions dominate. Another interesting finding is the formation of a radical cation from the 2,4-substituted azete by loss of a methyl radical. The fragmentation yield as a function of the collision energy for each of the 1,3,5-trisubstituted 2-pyrazolines was determined. Based on the fragmentation yield versus collision energy curves the relative fragmentation stabilities for the 1,3,5-trisubstituted 2-pyrazoline derivatives were also evaluated. 相似文献
104.
Guenther S Schäfer KC Balog J Dénes J Majoros T Albrecht K Tóth M Spengler B Takáts Z 《Journal of the American Society for Mass Spectrometry》2011,22(11):2082-2089
The feasibility of electrospray (ES) ionization of aerosols generated by electrosurgical disintegration methods was investigated.
Although electrosurgery itself was demonstrated to produce gaseous ions, post-ionization methods were implemented to enhance
the ion yield, especially in those cases when the ion current produced by the applied electrosurgical method is not sufficient
for MS analysis. Post-ionization was implemented by mounting an ES emitter onto a Venturi pump, which is used for ion transfer.
The effect of various parameters including geometry, high voltage setting, flow parameters, and solvent composition was investigated
in detail. Experimental setups were optimized accordingly. ES post-ionization was found to yield spectra similar to those
obtained by the REIMS technique, featuring predominantly lipid-type species. Signal enhancement was 20- to 50-fold compared
with electrosurgical disintegration in positive mode, while no improvement was observed in negative mode. ES post-ionization
was also demonstrated to allow the detection of non-lipid type species in the electrosurgical aerosol, including drug molecules.
Since the tissue specificity of the MS data was preserved in the ES post-ionization setup, feasibility of tissue identification
was demonstrated using different electrosurgical methods. 相似文献
105.
A pharmacophore is a model which represents the key physico-chemical interactions that mediate biological activity. There is a long history of using pharmacophore modeling methods to select subsets of compounds, focused towards a specific target of interest. This paper will review existing computational methods for deriving and comparing pharmacophore models. We outline a new classification of pharmacophore methods based on the abstraction of the underlying chemical interactions which embody a pharmacophore, and the methods available to quantitatively compare them. Within the context of this classification, example studies, using specific pharmacophore modeling methods for focused library selection, will be discussed. 相似文献
106.
Mixing of polyelectrolyte solutions with solutions of oppositely charged surfactants usually leads to phase separation in a certain concentration range. However, since the charge-neutralized polyelectrolyte/surfactant nanoparticles might be utilized as versatile nanocarriers of different substances, it would be desirable to prevent their aggregation for some applications. As it was revealed in earlier investigations, the complete suppression of precipitation may be achieved only in mixtures of ionic surfactants and appropriate copolymer polyelectrolytes with nonionic and ionic blocks. In this work, we present a method that could prevent phase separation in mixtures of homopolyelectrolytes and oppositely charged surfactants. Specifically, it is shown that nonaggregating electroneutral nanocomplexes of branched poly(ethylenimine) (PEI) and sodium dodecyl sulfate (SDS) can be prepared in the presence of the amphiphilic triblock copolymer Pluronic F108, provided that an adequate mixing protocol is used for preparation of the PEI/SDS/F108 mixtures. 相似文献
107.
Erzsébet Illés Erzsébet Takács András Dombi Krisztina Gajda-Schrantz Katalin Gonter László Wojnárovits 《Radiation Physics and Chemistry》2012,81(9):1479-1483
The intermediates and final products of ketoprofen degradation were investigated in 0.4 mmol dm?3 solution by pulse radiolysis and gamma radiolysis. For observation of final products UV?vis spectrophotometry and HPLC separation with diode array detection were used, and for identification MS was used. The reactions of ?OH lead to hydroxycyclohexadienyl type radical intermediates, in their further reactions hydroxylated derivatives of ketoprofen form as final products. The hydrated electron is scavenged by the carbonyl oxygen and the electron adduct protonates to ketyl radical ?OH is more effective in decomposing ketoprofen than hydrated electron. Chemical oxygen demand and total organic carbon content measurements on irradiated aerated solutions showed that using irradiation technology ketoprofen can be mineralised. The initial toxicity of the solution monitored by the Daphnia magna test steadily decreases with irradiation. Using 5 kGy dose no toxicity of the solution was detected with this test. 相似文献
108.
Dávid Csercsik Gábor Szederkényi Katalin M. Hangos 《Journal of mathematical chemistry》2012,50(1):1-8
In this paper it is shown that deficiency zero mass action reaction networks containing one terminal linkage class are parametrically
and therefore structurally unique with a fixed complex set. Clearly, weakly reversible deficiency zero networks with one linkage
class belong to this class. However, it is shown through an illustrative example that deficiency zero networks with several
linkage classes can have multiple dynamically equivalent realizations, even if the individual linkage classes are weakly reversible. 相似文献
109.
BÉLa Török Katalin Balázsik Imre Dékány MiháLy Bartók 《Molecular Crystals and Liquid Crystals》2013,570(2):339-344
Abstract Chirally modified hectorites (laponite RD) were prepared by ion exchange with (R)-and (S)-N-alkyl-phenylethyl ammonium salts. The structure of the chiral clay-organocomplexes were studied by X-ray diffraction and FT-IR-spectroscopy. Due to the low charge density of the laponite the organic modifiers lay on the inner surface of lamellae, no pillaring effect was observed. Using the chiral nanoreactors obtained in a catalytic process enantiodifferentiation was observed. 相似文献
110.
The conditions of structural dynamical similarity of two special classes of positive polynomial nonlinear systems, the class of quasi-polynomial systems (Brenig (1988) [1]) and that of reaction kinetic networks with mass action kinetics (Horn and Jackson (1972) [2]) are investigated in this Letter. It is shown that both system classes have an underlying reduced linear dynamics. By applying the theory of X-factorable systems (Samardzija et al. (1989) [9]), it can be shown that the reduced linear dynamics is qualitatively similar to the original one within the positive orthant when the original nonlinear system has a unique positive equilibrium point. 相似文献