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101.
Kara P Ozkan D Kerman K Meric B Erdem A Ozsoz M 《Analytical and bioanalytical chemistry》2002,373(8):710-716
The electrochemical behavior of hemin, an iron complex of porphyrin, on binding to DNA at a glassy carbon electrode (GCE) and in solution, is described. Hemin, which interacts with covalently immobilized calf thymus DNA, was detected by use of a bare GCE, a double-stranded DNA-modified GCE (dsDNA-modified GCE), and a single-stranded DNA-modified GCE (ssDNA-modified GCE), in combination with differential pulse voltammetry (DPV). The structural conformation of DNA was determined from changes in the voltammetric signals acquired on reduction of hemin. As a result of its large steric structure and anionic substitution on its porphyrin plane, hemin intercalates between the base pairs of dsDNA. A scan-rate study for hemin and the dsDNA-hemin complex were also performed to determine the electrochemical behavior of the complex. The partition coefficient was obtained from the peak currents measured when different concentrations of hemin were in the presence of dsDNA. By observing the oxidation signals of guanine, damage to DNA after reaction with hemin at the GCE surface was also detected. The electrochemical detection of hybridization between the covalently immobilized probe and its target sequence was detected by use of hemin. These results demonstrate the use of DNA biosensors in conjunction with hemin for electrochemical detection of hybridization and damage to DNA. 相似文献
102.
Uniform stability for solutions of a structural acoustics PDE model with no added dissipative feedback 下载免费PDF全文
A rate of rational decay is obtained for smooth solutions of a PDE model, which has been used in the literature to describe structural acoustic flows. This structural acoustics model is composed of two distinct PDE systems: (i) a wave equation, to model the interior acoustic flow within the given cavity Ω and (ii) a structurally damped elastic equation, to describe time‐evolving displacements along the flexible portion Γ0 of the cavity walls. Moreover, the extent of damping in this elastic component is quantified by parameter η∈[0,1]. The coupling between these two distinct dynamics occurs across the boundary interface Γ0. Our main result is the derivation of uniform decay rates for classical solutions of this particular structural acoustic PDE, decay rates that are obtained without incorporating any additional boundary dissipative feedback mechanisms. In particular, in the case that full Kelvin–Voight damping is present in fourth‐order elastic dynamics, that is, the structural acoustics system as it appears in the literature, solutions that correspond to smooth initial data decay at a rate of . By way of deriving these stability results, necessary a priori inequalities for a certain static structural acoustics PDE model are generated here; these inequalities ultimately allow for an application of a recently derived resolvent criterion for rational decay. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
103.
Senem Karahan Pelin Kose Elif Subasi Huseyin Alp Hamdi Temel 《Transition Metal Chemistry》2008,33(7):849-854
The hitherto unknown complexes, [M2(CO)6(μ-CO)(μ-L)], [M = Cr; 1, Mo; 2, W; 3] and [M2(CO)6(μ-CO)(μ-L′)], [M = Cr; 4, Mo; 5, W; 6] have been synthesized by the photochemical reactions of photogenerated intermediate, M(CO)5THF (M = Cr, Mo, W) with thio Schiff base ligands, N,N′-bis(2-aminothiophenol)-1,4-bis(2-carboxaldehydephenoxy)butane (H
2
L) and N,N′-bis(2-aminothiophenol)-1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane (H
2
L′). The complexes have been characterized by elemental analysis, LC-mass spectrometry, magnetic studies, FT-IR and 1H NMR spectroscopy. The spectroscopic studies show that H
2
L and H
2
L′ ligands are converted to benzothiazole derivatives, L and L′ after UV irradiation and coordinated to the central metal as bridging ligands via the central azomethine nitrogen and sulphur
atoms in 1–6. 相似文献
104.
The removal of textile dyes by diatomite earth 总被引:4,自引:0,他引:4
The adsorption of some textile dyes by diatomite was investigated using Sif Blau BRF (SB), Everzol Brill Red 3BS (EBR), and Int Yellow 5GF (IY). Adsorption of these textile dyes onto diatomite earth samples was studied by batch adsorption techniques at 30 degrees C. The adsorption behavior of textile dyes on diatomite samples was investigated using a UV-vis spectrophotometric technique. The effect of particle size of diatomite, diatomite concentration, the effect of initial dye concentrations, and shaking time on adsorption was investigated. Adsorption coverage over the surface of diatomite was studied using two well-known isotherm models: Langmuir's and Freundlich's. These results suggest that the dye uptake process mediated by diatomite has a potential for large-scale treatment of textile mill discharges. According to the equilibrium studies, the selectivity sequence can be given as IY > SB > EBR. Values of the removal efficiency of the dyes ranged from 28.60 to 99.23%. These results show that natural diatomite holds great potential to remove textile dyes from wastewater. 相似文献
105.
The application of 1H MAS NMR allows a detailed study of the behavior of ethylene glycol adsorbed in NaX zeolites which may be used to understand the effect of confinement. Typical changes in the chemical shift values for the CH2 and OH groups were found which are very sensitive to interactions between the molecules and the internal surfaces. This allows clear differentiation between molecules within the zeolite cages and those adsorbed at the outer surface of the zeolite grains and also allows study of the dynamics of the different species. Selective 1H T1 measurements were carried out for various pore-filling degrees where large differences were found in the thermal mobility. It is shown that for the molecules inside the supercages, a dynamic heterogeneity occurs which may be related to the competing influences of molecule-internal surface interactions and molecule-molecule interactions within a network of intermolecular hydrogen bonds. 相似文献
106.
Site‐Selective C−S Bond Formation at C−Br over C−OTf and C−Cl Enabled by an Air‐Stable,Easily Recoverable,and Recyclable Palladium(I) Catalyst 下载免费PDF全文
Thomas Scattolin Erdem Senol Dr. Guoyin Yin Dr. Qianqian Guo Prof. Dr. Franziska Schoenebeck 《Angewandte Chemie (International ed. in English)》2018,57(38):12425-12429
This report widens the repertoire of emerging PdI catalysis to carbon–heteroatom, that is, C?S bond formation. While Pd0‐catalyzed protocols may suffer from the formation of poisonous sulfide‐bound off‐cycle intermediates and lack of selectivity, the mechanistically diverse PdI catalysis concept circumvents these challenges and allows for C?S bond formation (S–aryl and S–alkyl) of a wide range of aryl halides. Site‐selective thiolations of C?Br sites in the presence of C?Cl and C?OTf were achieved in a general and a priori predictable fashion. Computational, spectroscopic, X‐ray, and reactivity data support dinuclear PdI catalysis to be operative. Contrary to air‐sensitive Pd0, the active PdI species was easily recovered in the open atmosphere and subjected to multiple rounds of recycling. 相似文献
107.
108.
109.
A simple method is proposed for the determination and speciation of Mn(II) and Mn(VII) in waters utilizing a macroporous resin, Amberlite XAD-7HP. The batch method was employed and flame atomic absorption spectrometry was used in all determinations. Amberlite XAD-7HP resin was shown to retain Mn(VII) between pH 4 and 12. If the solution contains only one of the species, either Mn(II) or Mn(VII), the resin behaves selectively depending on the pH of the solution. The elution from the sorbent was realized using K2C2O4 in HNO3. The efficiency of the method was checked via spike recovery experiments. The proposed method was successfully applied to industrial wastewater samples and quantitative recoveries (≥96.0%) confirmed the accuracy of the method. 相似文献
110.
In this study we consider a coupled system of partial differential equations (PDE's) which describes a certain structural acoustics interaction. One component of this PDE system is a wave equation, which serves to model the interior acoustic wave medium within a given three dimensional chamber Ω. This acoustic wave equation is coupled on a boundary interface Γ0 to a two dimensional system of thermoelasticity: this thermoelastic PDE is composed in part of a structural beam or plate equation, which governs the vibrations of flexible wall portion Γ0 of the chamber Ω. Moreover, this elastic dynamics is coupled to a heat equation which also evolves on Γ0, and which imparts a thermal damping onto the entire structural acoustic system. As we said, the interaction between the wave and thermoelastic PDE components takes place on the boundary interface Γ0, and involves coupling boundary terms which are above the level of finite energy. We analyze the stability properties of this coupled structural acoustics PDE model, in the absence of any additive feedback dissipation on the hard walls Γ1 of the boundary . Under a certain geometric assumption on Γ1, an assumption which has appeared in the literature in connection with structural acoustic flow, and which allows for the invocation of a recently derived microlocal boundary trace estimate, we show that classical solutions of this thermally damped structural acoustics PDE decay uniformly to zero, with a rational rate of decay. 相似文献