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101.
Berta Holló Marko V. Rodić Ljiljana S. Vojinović-Ješić Vukosava Živković-Radovanović Gordana Vučković Vukadin M. Leovac Katalin Mészáros Szécsényi 《Journal of Thermal Analysis and Calorimetry》2014,116(2):655-662
The synthesis of a potentially bioactive mixed-valence CoIII/CoII complex with 2-acetylpyridine S-methylisothiosemicarbazone (HL) ligand is described. The crystal and molecular structure of the formed [CoIIIL2][CoIICl3 py]·Me2CO (I) compound (py stands for pyridine) is determined by single-crystal X-ray crystallography. It’s thermal decomposition along with the decomposition of the ligand and six structurally related complexes with formulas [CoL2]NO3·MeOH (1), [CoL2]Br·MeOH (2), [CoL2]HSO4·MeOH (3), [CoL2]2[CoII(NCS)4] (4), [Co(HL)(L)]I2·2MeOH (5), and [Co(HL)(L)][CoIICl4]·MeOH (6) was determined by simultaneous TG/DSC measurements. The decomposition pattern is evaluated using TG/DTA-MS data. The results were related to the solvent/moisture content and the decomposition mechanism of the compounds. The antimicrobial activity of the ligand and of all the complexes was tested in vitro for selected gram-negative and gram-positive bacteria and fungi. The activity of the ligand against all tested bacteria is comparable with those obtained for standard antibiotics, while it is less active against fungi. Surprisingly, the activity of the complexes is very low. The low antimicrobial activity of the complexes may be in connection with their high thermodynamic and kinetic inertness in solution. The results are also supported by the relatively high thermal stability of the complexes. 相似文献
102.
Mario Jug Jasna Jablan Katalin Köver Tin Weitner Mario Gabričević 《Journal of inclusion phenomena and macrocyclic chemistry》2014,79(3-4):391-400
The thermodynamics and stoichiometry of zaleplon (ZAL) complexation with different cyclodextrin derivatives [β-CD, hydroxypropyl-β-cyclodextrin (HP-β-CD), randomly methylated-β-cyclodextrin (RAMEB), sulphobutylether-β-cyclodextrin (SBE-β-CD)] in aqueous solution was studied by spectrofluorimetry and 1H NMR spectroscopy in order to obtain a more general understanding of the driving forces behind the inclusion phenomena. Job’s plot derived from the NMR spectral data and statistical analysis of spectrofluorimetric titration data confirmed the formation of equimolar complexes in all systems tested, excluding the possibility of higher order complex formation. Furthermore, thermodynamic parameters obtained by both techniques gave similar and negative values of ΔG° for all complexes, indicating spontaneous inclusion of drug into CDs. From a thermodynamic point of view, two types of inclusions were determined. One is enthalpy driven ZAL complexation with β-CD, HP-β-CD and RAMEB, while the other is entropy driven complexation observed in the case of SBE-β-CD. The mechanisms behind each type of inclusion were discussed in detail. 相似文献
103.
V. ZeleÔák Z. Vargová Katalin Györyová E. Ve?erníková V. Balek 《Journal of Thermal Analysis and Calorimetry》2005,82(3):747-754
Summary Three copper acetate complex compounds, namely Cu(CH3COO)2(en)2·2H2O (I), Cu(CH3COO)2(tn)2(II) and Cu2(CH3COO)4(pyz) (III) (en=ethylenediamine, tn=1,3-diaminopropane, pyz=pyrazine), were prepared and characterized during heating in argon by thermogravimetry (TG), differential thermal analysis
(DTA) and evolved gas analysis (EGA) using mass spectrometry (MS). The results of infrared spectroscopy (IR) were evaluated
to be used as a spectroscopic criterion for the determination of the carboxylate binding mode in the compounds. 相似文献
104.
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
105.
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
106.
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
107.
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
108.
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
109.
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
110.
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