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排序方式: 共有168条查询结果,搜索用时 203 毫秒
91.
Onidas D Gustavsson T Lazzarotto E Markovitsi D 《Physical chemistry chemical physics : PCCP》2007,9(37):5143-5148
Polymeric and oligomeric DNA helices, poly(dAdT).poly(dAdT) and (dAdT)(10).(dAdT)(10), composed of 200-400 and 20 adenine-thymine base pairs, respectively, are studied by fluorescence upconversion. Fluorescence decays, anisotropy decays and time-resolved spectra, obtained for this alternating base sequence, are compared with those determined previously for the homopolymeric sequence (dA)(n).(dT)(n). It is shown that identical fluorescence decays may correspond to quite different anisotropy decays and vice versa, both varying with the emission wavelength, the base sequence and the duplex size. Our observations cannot be explained in terms of monomer and excimer emission exclusively, as concluded in the past on the basis of steady-state measurements. Excitons also contribute to the fluorescence. These are rapidly trapped by excimers, characterized by long-lived weak emission. 相似文献
92.
Dimitra Tagkouli Thalia Tsiaka Eftichia Kritsi Marina Sokovi Vassilia J. Sinanoglou Dimitra Z. Lantzouraki Panagiotis Zoumpoulakis 《Molecules (Basel, Switzerland)》2022,27(7)
Wine lees, a sub-exploited byproduct of vinification, is considered a rich source of bioactive compounds, such as (poly)phenols, anthocyanins and tannins. Thus, the effective and rapid recovery of these biomolecules and the assessment of the bioactive properties of wine lees extracts is of utmost importance. Towards this direction, microwave-assisted extraction (MAE) factors (i.e., extraction time, microwave power and solvent/material ratio) were optimized using experimental design models in order to maximize the (poly)phenolic yield of the extracts. After optimizing the MAE process, the total phenolic content (TPC) as well as the antiradical, antioxidant and antimicrobial activity of the extracts were evaluated. Furthermore, Fourier transform infrared spectroscopy (FTIR) was employed to investigate the chemical profile of wine lees extracts. Red varieties exhibited higher biological activity than white varieties. The geographical origin and fermentation stage were also considered as critical factors. The white variety Moschofilero presented the highest antioxidant, antiradical and antimicrobial activity, while Merlot and Agiorgitiko samples showed noteworthy activities among red varieties. Moreover, IR spectra confirmed the presence of sugars, amino acids, organic acids and aromatic compounds. Thus, an efficient, rapid and eco-friendly process was proposed for further valorization of wine lees extracts. 相似文献
93.
Sotirios Nik. Longinos Dionisia Dimitra Longinou Nurbala Myrzakhmetova Nazgul Akimbayeva Mariamkul Zhursumbaeva Kaldibek Abdiyev Zhexenbek Toktarbay Mahmut Parlaktuna 《Molecules (Basel, Switzerland)》2022,27(14)
Heat generation during gas hydrate formation is an important problem because it reduces the amount of water and gas that become gas hydrates. In this research work, we present a new design of an impeller to be used for hydrate formation and to overcome this concern by following the hydrodynamic literature. CH4 hydrate formation experiments were performed in a 5.7 L continuously stirred tank reactor using a butterfly turbine (BT) impeller with no baffle (NB), full baffle (FB), half baffle (HB), and surface baffle (SB) under mixed flow conditions. Four experiments were conducted separately using single and dual impellers. In addition to the estimated induction time, the rate of hydrate formation, hydrate productivity and hydrate formation rate, constant for a maximum of 3 h, were calculated. The induction time was less for both single and dual-impeller experiments that used full baffle for less than 3 min and more than 1 h for all other experiments. In an experiment with a single impeller, a surface baffle yielded higher hydrate growth with a value of 42 × 10−8 mol/s, while in an experiment with dual impellers, a half baffle generated higher hydrate growth with a value of 28.8 × 10−8 mol/s. Both single and dual impellers achieved the highest values for the hydrate formation rates that were constant in the full-baffle experiments. 相似文献
94.
Dr. Antonella Paladino Dr. Mark R. Woodford Dr. Sarah J. Backe Dr. Rebecca A. Sager Dr. Priyanka Kancherla Dr. Michael A. Daneshvar Dr. Victor Z. Chen Dimitra Bourboulia Dr. Elham F. Ahanin Dr. Chrisostomos Prodromou Dr. Greta Bergamaschi Dr. Alessandro Strada Dr. Marina Cretich Dr. Alessandro Gori Dr. Marina Veronesi Dr. Tiziano Bandiera Renzo Vanna Dr. Gennady Bratslavsky Stefano A. Serapian Dr. Mehdi Mollapour Prof. Dr. Giorgio Colombo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(43):9459-9465
Protein folding quality control in cells requires the activity of a class of proteins known as molecular chaperones. Heat shock protein-90 (Hsp90), a multidomain ATP driven molecular machine, is a prime representative of this family of proteins. Interactions between Hsp90, its co-chaperones, and client proteins have been shown to be important in facilitating the correct folding and activation of clients. Hsp90 levels and functions are elevated in tumor cells. Here, we computationally predict the regions on the native structures of clients c-Abl, c-Src, Cdk4, B-Raf and Glucocorticoid Receptor, that have the highest probability of undergoing local unfolding, despite being ordered in their native structures. Such regions represent potential ideal interaction points with the Hsp90-system. We synthesize mimics spanning these regions and confirm their interaction with partners of the Hsp90 complex (Hsp90, Cdc37 and Aha1) by Nuclear Magnetic Resonance (NMR). Designed mimics selectively disrupt the association of their respective clients with the Hsp90 machinery, leaving unrelated clients unperturbed and causing apoptosis in cancer cells. Overall, selective targeting of Hsp90 protein–protein interactions is achieved without causing indiscriminate degradation of all clients, setting the stage for the development of therapeutics based on specific chaperone:client perturbation. 相似文献
95.
Szymańska B Skrzypek D Kovala-Demertzi D Staninska M Demertzis MA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,63(3):518-523
The interaction of copper(II) and manganese(II) with pipemidic acid, Hpipem, afforded the complexes [Cu(pipem)(2)(H(2)O)] x 2H(2)O, 1 and [Mn(pipem)(2)(H(2)O)], 2. The new complexes have been characterised by elemental analyses, infrared, UV-vis and X-band EPR spectroscopy in the temperature range from 4 to 300 K. The monoanion, pipem, exhibits O,O ligation through the carbonyl and carboxylato oxygen atoms. Five coordinate square-pyramid configuration has been proposed for 1 and 2, and the fifth apical position is occupied by a coordinated water molecule. 相似文献
96.
97.
George E. Magoulas Thomas Garnelis Constantinos M. Athanassopoulos Dionissios Papaioannou George Mattheolabakis Konstantinos Avgoustakis Dimitra Hadjipavlou-Litina 《Tetrahedron》2012,68(35):7041-7049
(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C60, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine. 相似文献
98.
Eleftheriou Georgios Tsabaris Christos Papageorgiou Dimitra K. Patiris Dionisis L. Androulakaki Effrosini G. Pappa Filothei K. 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(2):655-671
Journal of Radioanalytical and Nuclear Chemistry - Chronological records and sedimentation rates of coastal sediment cores from different aquatic environments of NE Mediterranean are reported.... 相似文献
99.
100.
Zoi Terzopoulou Myrsini Papageorgiou George Z. Kyzas Dimitrios N. Bikiaris Dimitra A. Lambropoulou 《Analytica chimica acta》2016
In the present study, a molecularly imprinted solid-phase microextraction fiber (MIP-SPMEf) was synthesized and applied for the selective removal and extraction of the antiviral drug, abacavir (ABA). Morphology and structure characterization of fibers were performed by scanning electron microscopy and Fourier transform infrared spectra, respectively. The effects on the adsorption behavior of the process parameters were studied and the equilibrium data were fitted by the Langmuir, Freundlich and Langmuir-Freundlich models. The maximum adsorption capability (Qmax) was determined by Langmuir- Freundlich model and was 149 mg/g for MIP-SPMEf. In the next step, SPME methodology followed by liquid desorption and liquid chromatography with mass spectrometry (LC/MS) has been developed and evaluated for the determination of the target compound in environmental and biological matrices (surface waters, wastewaters and urine). Parameters that could influence SPME efficiency were investigated. Then, optimization of stirring speed, extraction time and salt content was carried out by using a central composite design (CCD) and response surface methodology (RSM). A quadratic model between dependent and independent variables was built. Under the optimum conditions (extraction time 40 min, stirring rate 650 rpm and salt content 0.3% NaCl w/v) the validated method presented a high sensitivity and selectivity with LODs and LOQs in the range of 10.1–13.6 and 33.3–43.9 ng/L, respectively. The developed method was successfully applied to the analysis of ABA in real samples. The percentage extraction efficiency ranged from 88 to 99% revealing good accuracy and absence of matrix effects. 相似文献