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排序方式: 共有121条查询结果,搜索用时 9 毫秒
61.
Ioannou Katerina Hadjiyiannis Pantelis Liatsou Ioanna Pashalidis Ioannis 《Journal of Radioanalytical and Nuclear Chemistry》2019,320(2):425-432
The removal of U(VI) by biochar fibers from aqueous solutions has been investigated prior and after MnO2 surface-deposition. The removal efficiency has been studied as a function of pH, U(VI) concentration, ionic strength, temperature and contact time. The fibers morphology and surface complexes were analyzed by SEM–EDX and FTIR, respectively. Evaluation of the experimental data indicates that the composite presents extraordinary adsorption capacity (qmax = 3.8 mmol g−1, 904 mg g−1), which is attributed to the formation of inner-sphere surface complexes, and that the adsorption reaction is a relatively fast, endothermic and entropy-driven process.
相似文献62.
Stephan Wagner Hendrik Auerbach Claudia E. Tait Ioanna Martinaiou Shyam C. N. Kumar Christian Kübel Ilya Sergeev Hans‐Christian Wille Jan Behrends Juliusz A. Wolny Volker Schünemann Ulrike I. Kramm 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(31):10596-10602
Fe–N–C catalysts are very promising materials for fuel cells and metal–air batteries. This work gives fundamental insights into the structural composition of an Fe–N–C catalyst and highlights the importance of an in‐depth characterization. By nuclear‐ and electron‐resonance techniques, we are able to show that even after mild pyrolysis and acid leaching, the catalyst contains considerable fractions of α‐iron and, surprisingly, iron oxide. Our work makes it questionable to what extent FeN4 sites can be present in Fe–N–C catalysts prepared by pyrolysis at 900 °C and above. The simulation of the iron partial density of phonon states enables the identification of three FeN4 species in our catalyst, one of them comprising a sixfold coordination with end‐on bonded oxygen as one of the axial ligands. 相似文献
63.
Metric Entropy of Convex Hulls in Banach Spaces 总被引:4,自引:0,他引:4
The paper presents diverse methods for estimating the coveringnumber of a precompact subset of a Banach space when the entropyof the set of its extremal points is already known. In the caseof a Hilbert space, the Gelfand diameters of the subset arealso estimated. 相似文献
64.
Ioanna Kyrezi 《Proceedings of the American Mathematical Society》2000,128(8):2393-2403
We give estimates for the entropy numbers and the Gelfand diameters of the symmetric convex hull of a finite number of points in a Banach or a Hilbert space.
65.
Ioanna Kostopoulou Andromachi Tzani Nestor-Ioannis Polyzos Maria-Anna Karadendrou Eftichia Kritsi Eleni Pontiki Thalia Liargkova Dimitra Hadjipavlou-Litina Panagiotis Zoumpoulakis Anastasia Detsi 《Molecules (Basel, Switzerland)》2021,26(9)
2′-hydroxy-chalcones are naturally occurring compounds with a wide array of bioactivity. In an effort to delineate the structural features that favor antioxidant and lipoxygenase (LOX) inhibitory activity, the design, synthesis, and bioactivity profile of a series of 2′-hydroxy-chalcones bearing diverse substituents on rings A and B, are presented. Among all the synthesized derivatives, chalcone 4b, bearing two hydroxyl substituents on ring B, was found to possess the best combined activity (82.4% DPPH radical scavenging ability, 82.3% inhibition of lipid peroxidation, and satisfactory LOX inhibition value (IC50 = 70 μM). Chalcone 3c, possessing a methoxymethylene substituent on ring A, and three methoxy groups on ring B, exhibited the most promising LOX inhibitory activity (IC50 = 45 μM). A combination of in silico techniques were utilized in an effort to explore the crucial binding characteristics of the most active compound 3c and its analogue 3b, to LOX. A common H-bond interaction pattern, orienting the hydroxyl and carbonyl groups of the aromatic ring A towards Asp768 and Asn128, respectively, was observed. Regarding the analogue 3c, the bulky (-OMOM) group does not seem to participate in a direct binding, but it induces an orientation capable to form H-bonds between the methoxy groups of the aromatic ring B with Trp130 and Gly247. 相似文献
66.
Integrated Deadenylase Genetic Association Network and Transcriptome Analysis in Thoracic Carcinomas
Athanasios Kyritsis Eirini Papanastasi Ioanna Kokkori Panagiotis Maragozidis Demetra S. M. Chatzileontiadou Paschalina Pallaki Maria Labrou Sotirios G. Zarogiannis George P. Chrousos Dimitrios Vlachakis Konstantinos I. Gourgoulianis Nikolaos A. A. Balatsos 《Molecules (Basel, Switzerland)》2022,27(10)
67.
Maria V. Vavoura Ioannis K. Karabagias Ioanna S. Kosma Anastasia V. Badeka Michael G. Kontominas 《Molecules (Basel, Switzerland)》2022,27(19)
The present study focused on the possibility of differentiating fresh-unprocessed orange juice according to botanical origin (variety), based on the use of conventional physico-chemical parameters, flavonoids, and volatile compounds, in combination with chemometrics. For this purpose, oranges from seven different varieties were collected during the harvest years of 2013–2014 and 2014–2015 from central and southern Greece. The physico-chemical parameters that were determined included: electrical conductivity, acidity, pH, and total soluble solids. The flavonoids: hesperidin, neohespseridin, quercetin, naringin, and naringenin were determined using high-performance liquid chromatography (HPLC-DAD). Finally, volatile compounds were determined using headspace solid-phase micro-extraction in combination with gas chromatography-mass spectrometry (HS-SPME/GC-MS). Statistical treatment of data by multivariate techniques showed that orange juice variety had a significant (p < 0.05) impact on the above analytical parameters. The classification rate for the differentiation of orange juice according to orange variety using multivariate analysis of variance (MANOVA) and linear discriminant analysis (LDA) was 89.3%, based on the cross-validation method. 相似文献
68.
Medical errors associated with IV preparation and administration procedures in a hospital workflow can even cost human lives due to the direct effect they have on patients. A large number of such incidents, which have been reported in bibliography up to date, indicate the urgent need for their prevention. This study aims at proposing an analytical methodology for identifying and quantifying IV drugs before their administration, which has the potential to be fully harmonized with clinical practices. More specifically, it reports on the analysis of a piperacillin (PIP) and tazobactam (TAZ) IV formulation, using Raman spectroscopy. The simultaneous analysis of the two APIs in the same formulation was performed in three stages: before reconstitution in the form of powder without removing the substance out of the commercial glass bottle (non-invasively), directly after reconstitution in the same way, and just before administration, either the liquid drug is placed in the infusion set (on-line analysis) or a minimal amount of it is transferred from the IV bag to a Raman optic cell (at-line analysis). Except for the successful identification of the APIs in all cases, their quantification was also achieved through calibration curves with correlation coefficients ranging from 0.953 to 0.999 for PIP and from 0.965 to 0.997 for TAZ. In any case, the whole procedure does not need more than 10 min to be completed. The current methodology, based on Raman spectroscopy, outweighs other spectroscopic (UV/Vis, FT-IR/ATR) or chromatographic (HPLC, UHPLC) protocols, already applied, which are invasive, costly, time-consuming, not environmentally friendly, and require specialized staff and more complex sample preparation procedures, thus exposing the staff to hazardous materials, especially in cases of cytotoxic drugs. Such an approach has the potential to bridge the gap between experimental setup and clinical implementation through exploitation of already developed handheld devices, along with the presence of digital spectral libraries. 相似文献
69.
H. Esra Oguztürk Leona J. Bauer Ioanna Mantouvalou Birgit Kanngieβ er Orlin D. Velev Michael Gradzielski 《Particle & Particle Systems Characterization》2021,38(6):2000328
The preparation of fumed silica-based anisometric supraparticles with well-defined catalytically active patches suitable for self-propulsion is presented here. These sub-millimeter-sized particles can self-propel as they contain Pt-covered magnetite (Fe3O4) nanoparticles, where the Pt can decompose catalytically a “fuel” like H2O2 and thereby propel the supraparticles. By their magnetic properties, the catalytically active nanoparticles can be concentrated in patches on the supraparticle surface. The goal is to obtain robust supraparticles with well-defined patchiness and long-time stability during self-propulsion through evaporation-induced self-assembly (EISA) on a superhydrophobic surface. The latter is a major issue as oxygen evolution can lead to the disintegration of the supraparticles. Therefore, enhanced mechanical stability is sought using a number of different additives, where the best results are obtained by incorporating polystyrene microspheres followed by heat treatment or reinforcement with microfibrillated cellulose (MFC) and sodium trisilicate (Na2SiO3). The detailed internal structure of the different types of particles is investigated by confocal micro-X-ray fluorescence spectroscopy (CMXRF), which allows for precisely locating the catalytic Fe3O4@Pt nanoparticles within the supraparticles with a resolution in the µm range. The insights on the supraparticle structure, together with their long-time stability, allow fabricating optimized patchy supraparticles for potential applications in propulsion-enhanced catalysis. 相似文献
70.