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排序方式: 共有119条查询结果,搜索用时 62 毫秒
71.
Prakasam Gayathri Prof. Annamalai Senthil Kumar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(50):17103-17112
A new biomimetic functional system having an impure multiwalled carbon nanotube (MWCNT‐Fe)–chitosan biopolymer (H2N–CHIT) chemically modified glassy carbon electrode (GCE/[MWCNT‐Fe:H2N‐CHIT]) has been developed and demonstrated efficient hydrogen peroxide electrocatalytic and electrochemical sensing applications in pH 7 phosphate buffer solution (PBS). The hybrid system showed a stable and well‐defined surface confined redox peak at an apparent electrode potential, E°′=?0.22 V versus Ag/AgCl with surface excess value 13.63 nmol cm?2. Physicochemical characterizations of the hybrid by using FESEM, TEM, Raman spectroscopy, FTIR, and various control electrochemical experiments revealed that the iron impurity in the MWCNT interacted with the amino functional group of the chitosan polymer and thereby formed an unique complex‐like structure ([MWCNT‐FeIII/II:NH2‐CHIT]), similar to heme peroxidase with a central FeIII/II‐redox‐active site. The biomimetic system followed Michaelis–Menten‐type reaction kinetics for the H2O2 reduction reaction with a KM value of 0.23 mM . At pH 7, amperometric i–t sensing and flow‐injection analysis of H2O2 on the biomimetic system showed calibration plots in windows 5–500 and 50–2500 μM , with detection‐limit values of 2.3 and 9.7 μM , respectively. Unlike most of the previously reported systems that undergo serious interferences in physiological pH, the biomimetic system displayed a remarkable tolerance to other co‐existing interferants (such as cysteine, ascorbic acid, uric acid, nitrate, and nitrite), at a H2O2 detection potential similar to the peroxidase enzyme. The ability of the biosensor system to perform routine analyses was demonstrated by the detection of H2O2 present in simulated milk and clinical and cosmetic samples with appreciable recovery values. 相似文献
72.
Gayathri Selvaraju Thean Chor Leow Abu Bakar Salleh Yahaya M. Normi 《Molecules (Basel, Switzerland)》2020,25(24)
Previously, a hypothetical protein (HP) termed Bleg1_2437 (currently named Bleg1_2478) from Bacillus lehensis G1 was discovered to be an evolutionary divergent B3 subclass metallo-β-lactamase (MBL). Due to the scarcity of clinical inhibitors for B3 MBLs and the divergent nature of Bleg1_2478, this study aimed to design and characterise peptides as inhibitors against Bleg1_2478. Through in silico docking, RSWPWH and SSWWDR peptides with comparable binding energy to ampicillin were obtained. In vitro assay results showed RSWPWH and SSWWDR inhibited the activity of Bleg1_2478 by 50% at concentrations as low as 0.90 µM and 0.50 µM, respectively. At 10 µM of RSWPWH and 20 µM of SSWWDR, the activity of Bleg1_2478 was almost completely inhibited. Isothermal titration calorimetry (ITC) analyses showed slightly improved binding properties of the peptides compared to ampicillin. Docked peptide–protein complexes revealed that RSWPWH bound near the vicinity of the Bleg1_2478 active site while SSWWDR bound at the center of the active site itself. We postulate that the peptides caused the inhibition of Bleg1_2478 by reducing or blocking the accessibility of its active site from ampicillin, thus hampering its catalytic function. 相似文献
73.
N. Chandrashekhar V. Gayathri N. M. Nanje Gowda 《Magnetic resonance in chemistry : MRC》2009,47(8):666-673
Reactions of rhodium(III) halides with multidentate N,S‐heterocycles, (LH3) 1,3,5‐tris(benzimidazolyl)benzene (L1H3; 1 ), 1,3,5‐tris(N‐methylbenzimidazolyl) benzene (L2H3; 2 ) and 1,3,5‐tris(benzothiazolyl)benzene (L3H3; 3 ), in the molar ratio 1:1 in methanol–chloroform produced mononuclear cyclometallated products of the composition [RhX2(LH2)(H2O)] (X = Cl, Br, I; LH2 = L1H2, L2H2, L3H2). When the metal to ligand ( 1–3 or 1,2,4,5‐tetrakis(benzothiazolyl)benzene [L4H2; 4 ]) molar ratio was 2:1, the reactions yielded binuclear complexes of the compositions [Rh2Cl5(LH2)(H2O)3] (LH2 = L1H2, L2H2, L3H2) and [Rh2X4(L4)(H2O)2] (X = Cl, Br, I). Elemental analysis, IR and 1H nuclear magnetic resonance (NMR) chemical shifts supported the binuclear nature of the complexes. Cyclometallation was detected by conventional 13C NMR spectra that showed a doublet around ~190 ppm. Cyclometallation was also detected by gradient‐enhanced heteronuclear multiple bond correlation (g‐HMBC) experiment that showed cross‐peaks between the cyclometallated carbon and the central benzene ring protons of 1–3 . Cyclometallation was substantiated by two‐dimensional 1H? 1H correlated experiments (gradiant‐correlation spectroscopy and rotating frame Overhauser effect spectroscopy) and 1H? 13C single bond correlated two‐dimensional NMR experiments (gradient‐enhanced heteronuclear single quantum coherence). The 1H? 15N g‐HMBC experiment suggested the coordination of the heterocycles to the metal ion via tertiary nitrogen. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
74.
Gayathri S. S. Kumar R. Dhanalakshmi Samiappan Kaushik Brajesh Kumar Haghparast Majid 《International Journal of Theoretical Physics》2021,60(8):2823-2835
International Journal of Theoretical Physics - Quantum circuits for performing an arithmetic operation are necessary for the implementation of quantum computing peripherals. An effective quantum... 相似文献
75.
76.
Julio R. Pinzón Claudia M. Cardona Dr. Maria Ángeles Herranz Dr. Marta E. Plonska‐Brzezinska Dr. Amit Palkar Andreas J. Athans Dr. Nazario Martín Prof. Dr. Antonio Rodríguez‐Fortea Dr. Josep M. Poblet Prof. Dr. Giovanni Bottari Dr. Tomás Torres Prof. Dr. S. Shankara Gayathri Dr. Dirk M. Guldi Prof. Dr. Luis Echegoyen Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(4):807-807
77.
Sanjay Roy Gayathri Loganathan Dhanasekaran Dharumadurai Mohammad A. Akbarsha 《Journal of Coordination Chemistry》2017,70(12):2128-2147
The interactions of copper complex (CuQ2) of 1-amino-4-hydroxy-9,10-anthraquinone (QH) with calf thymus DNA, anionic surfactant sodium dodecyl sulfate (SDS), and cationic surfactant cetyltrimethylammonium bromide (CTAB) were investigated in an aqueous solution at physiological pH (7.4). Affinities of such molecule to DNA and surfactant micelles, a model for a biological membrane, are important in determining its biological action. Using different models, various binding parameters were evaluated in both of molecule–DNA interaction and molecule–surfactant interaction. The study showed that hydrophobic interaction plays a major role in the binding of CuQ2 to surfactant micelles. In addition, the hydrophobic interaction has an important role in the distribution of CuQ2 between micelle-water phases. Gibbs free energy for the binding and distribution of CuQ2 between the bulk aqueous medium and surfactant micelles were calculated. In order to correlate the physicochemical properties deciphered from the aforementioned studies with the biological property of the molecule, CuQ2 was treated with MDA-MB-231 breast adenocarcinoma cells where it was found that the molecule affects the viability of the cancer cells. Fluorescent staining of the treated cells with AO/EB and Hoechst indicated that the CuQ2 induces apoptosis, suggesting its use in the treatment of breast cancer. 相似文献
78.
This paper is aimed at identifying critical microstructural parameters that cause local stress concentration due to load shedding between microstructural regions of varying strengths. This stress is viewed as one of the fundamental reasons for crack initiation in Ti-6242. A rate dependent, anisotropic, elasto-crystal plasticity based finite element model (CPFEM) for poly-phase Ti-6242 is used in this study to identify the critical variables responsible for localized stress concentration due to load shedding. The model can account for various microstructural features like grain size, orientation and misorientation distributions. Various microstructural variables, such as crystal orientation, misorientation, grain size, Schmid factor and composition of phases, are considered in a detailed parametric study. Critical combinations of these parameters that result in high stress due to load shedding are identified. Finally, load shedding in a microstructure model of polycrystalline Ti-6242 is discussed from the results of CPFEM simulations. The model is statistically equivalent with respect to features observed in OIM scans. 相似文献
79.
Gayathri Virupaiah Leelamani Esapathi G. Gowda Nadur M. N. Reddy Giddanahalli K. N. 《Transition Metal Chemistry》2000,25(4):450-455
Complexes of the type [Rh(diolefin)(μ-X)]2 [X = Cl or Br; diolefin = cod (cycloocta-1,5-diene) or nbd (norbornadiene)] undergo dihalobridge cleavage with 2-substituted
benzimidazoles to produce mononuclear complexes, RhX(diolefin)(R-BzlH) (R = α-Py or Ph), and N-heterocycle bridged dimers,
[RhX(diolefin)]2(μ-N–N) (N–N = β-PyBzlH or γ-PyBzlH). Facile replacement ofone or both diolefins by CO occurs in the products to yield the
corresponding di/tetracarbonyl complexes. Probable structures have been proposed for the complexes on the basis of physical,
i.r., far-i.r. and 1H- and 13C-n.m.r. spectral techniques and FAB-MS.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
80.
Feng L Radhakrishnan SG Mizorogi N Slanina Z Nikawa H Tsuchiya T Akasaka T Nagase S Martín N Guldi DM 《Journal of the American Chemical Society》2011,133(19):7608-7618
Two stable electron donor-acceptor conjugates, that is, 3 and 5b, employing La(2)@I(h)-C(80) and Sc(3)N@I(h)-C(80), on one hand, and zinc tetraphenylporphyrin, on the other hand, have been prepared via [1+2] cycloaddition reactions of a diazo precursor. Combined studies of crystallography and NMR suggest a common (6,6)-open addition pattern of 3 and 5b. Still, subtly different conformations, that is, a restricted and a comparatively more flexible topography, emerge for 3 and 5b, respectively. In line with this aforementioned difference are the electrochemical assays, which imply appreciably stronger I(h)-C(80)/ZnP interactions in 3 when compared to those in 5b. Density functional calculations reveal significant attractions between the two entities of these conjugates, as well as their separately localized HOMOs and LUMOs. The geometrical conformations and LUMO distributions of 3 and 5b, at our applied computational level, are slightly varied with their different endohedral clusters. The clusters also exert different impact on the excited state reactivity of the conjugates. For example, 3 undergoes, upon photoexcitation, a fast charge separation process and yields a radical ion pair, whose nature, namely, (La(2)@C(80))(?-)-(ZnP)(?+)) versus (La(2)@C(80))(?+)-(ZnP)(?-)), varies with solvent polarity. 5b, on the other hand, afforded the same (Sc(3)N@C(80))(?-)-(ZnP)(?+)) radical ion pair regardless of the solvent. 相似文献