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111.
It is shown that the universal set of quantum logic gates can be realized using solid-state quantum bits based on coherent electron transport in quantum wires. The elementary quantum bits are realized with a proper design of two quantum wires coupled through a potential barrier. Numerical simulations show that (a) a proper design of the coupling barrier allows one to realize any one-qbit rotation and (b) Coulomb interaction between two qbits of this kind allows the implementation of the CNOT gate. These systems are based on a mature technology and seem to be integrable with conventional electronics. 相似文献
112.
Evidence for Degradation of the Chrome Yellows in Van Gogh’s Sunflowers: A Study Using Noninvasive In Situ Methods and Synchrotron‐Radiation‐Based X‐ray Techniques
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Dr. Letizia Monico Prof. Koen Janssens Dr. Ella Hendriks Frederik Vanmeert Dr. Geert Van der Snickt Dr. Marine Cotte Dr. Gerald Falkenberg Prof. Brunetto Giovanni Brunetti Dr. Costanza Miliani 《Angewandte Chemie (International ed. in English)》2015,54(47):13923-13927
This paper presents firm evidence for the chemical alteration of chrome yellow pigments in Van Gogh’s Sunflowers (Van Gogh Museum, Amsterdam). Noninvasive in situ spectroscopic analysis at several spots on the painting, combined with synchrotron‐radiation‐based X‐ray investigations of two microsamples, revealed the presence of different types of chrome yellow used by Van Gogh, including the lightfast PbCrO4 and the sulfur‐rich PbCr1?xSxO4 (x≈0.5) variety that is known for its high propensity to undergo photoinduced reduction. The products of this degradation process, i.e., CrIII compounds, were found at the interface between the paint and the varnish. Selected locations of the painting with the highest risk of color modification by chemical deterioration of chrome yellow are identified, thus calling for careful monitoring in the future. 相似文献
113.
This paper is devoted to the analysis of charged superselection sectors in the framework of the locally covariant quantum
field theories. We shall analyze sharply localizable charges, and use net-cohomology of J.E. Roberts as a main tool. We show
that to any 4-dimensional globally hyperbolic spacetime a unique, up to equivalence, symmetric tensor -category with conjugates (in case of finite statistics) is attached; to any embedding between different spacetimes, the
corresponding categories can be embedded, contravariantly, in such a way that all the charged quantum numbers of sectors are
preserved. This entails that to any spacetime is associated a unique gauge group, up to isomorphisms, and that to any embedding
between two spacetimes there corresponds a group morphism between the related gauge groups. This form of covariance between
sectors also brings to light the issue whether local and global sectors are the same. We conjecture this holds that at least
on simply connected spacetimes. It is argued that the possible failure might be related to the presence of topological charges.
Our analysis seems to describe theories which have a well defined short-distance asymptotic behaviour. 相似文献
114.
Brunetti FG Herrero MA Muñoz Jde M Giordani S Díaz-Ortiz A Filippone S Ruaro G Meneghetti M Prato M Vázquez E 《Journal of the American Chemical Society》2007,129(47):14580-14581
We report a new approach that uses microwaves to rapidly functionalize carbon nanotubes by using 1,3-dipolar cycloaddition of aziridines, well-known precursors to azomethine ylides, in solvent-free conditions. The efficiency of our microwave-mediated protocol is confirmed by comparison to a similar protocol in classical conditions for the azomethine ylides in DMF. Under these latter conditions, the reaction proceeds in 5 days (against 1 h under microwave irradiation), and the functionalization degree is much lower, as confirmed by thermogravimetric analysis and Raman spectroscopy. With our procedure, we easily scale-up the reaction up to 250 mg of functionalized MWNT in 1 h. We also provide an indirect proof of the covalent sidewall functionalization of the tubes. 相似文献
115.
Lucia Recinella Annalisa Chiavaroli Viviana di Giacomo Marco Daniel Antolini Alessandra Acquaviva Sheila Leone Luigi Brunetti Luigi Menghini Gunes Ak Gokhan Zengin Simonetta Cristina Di Simone Claudio Ferrante Giustino Orlando 《Molecules (Basel, Switzerland)》2021,26(1)
Tanacetum parthenium (feverfew) has traditionally been employed as a phytotherapeutic remedy in the treatment of migraine. In this study, a commercial T. parthenium water extract was investigated to explore its anti-inflammatory and neuromodulatory effects. Isolated mouse cortexes were exposed to a K+ 60 mM Krebs-Ringer buffer and treated with T. parthenium water extract. The prostaglandin E2 (PGE2) level, brain-derived neurotrophic factor (BDNF), interleukin-10 (IL-10), and IL-1β gene expression were evaluated in the cortex. The effects on dopamine (DA) release and dopamine transporter (DAT) gene expression were assayed in hypothalamic HypoE22 cells. A bioinformatics analysis was conducted to further investigate the mechanism of action. The extract was effective in reducing cortex PGE2 release and IL-1β gene expression. In the same experimental system, IL-10 and BDNF gene expressions increased, and in HypoE22 cells, the extract decreased the extracellular dopamine level and increased the DAT gene expression due to the direct interaction of parthenolide with the DAT. Overall, the present findings highlight the efficacy of T. parthenium water extract in controlling the inflammatory pathways that occur during cortical-spreading depression. Additionally, the inhibition of the hypothalamic DA release observed in this study further supports the role of dopaminergic pathways as key targets for novel pharmacological approaches in the management of migraine attacks. 相似文献
116.
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118.
Let p be an odd prime, M be an unstable locally finite module over the Steenrod algebra, and let ${\Phi_{S}}$ be the localization out of the Euler class of the mod-p cohomology ring of the group Z/p. We prove that the Singer evaluation map ${d : \Phi_S^{GL_{1}} \otimes M \longrightarrow M }$ is dually related to a total operation ${\chi P : M \longrightarrow \Phi_S^{GL_{1}} \otimes M}$ . We determine the exotic ${\mathcal A (p)}$ -module structure on the target which makes ?? P an ${\mathcal A (p)}$ -linear map, give a new proof of the Adem relations and find some new identities involving the Bockstein and the pth reduced powers. 相似文献
119.
Francesca Rosi Marco Paolantoni Catia Clementi Brenda Doherty Costanza Miliani Brunetto G. Brunetti Antonio Sgamellotti 《Journal of Raman spectroscopy : JRS》2010,41(4):452-458
Resonance Raman spectroscopy has been utilized to identify vegetal and animal dyes and lakes. These compounds have been used by artists since antiquity, and their identification has important implications in art history and conservation. The resonance condition is useful when working with real ancient objects so as to enhance the Raman scattering of chromophores with respect to the strong signal of the matrix, such as the textile or parchment over which the colorant is supported. The strong fluorescence that generally characterizes the resonance Raman spectra was eliminated by using subtracted shifted Raman spectroscopy (SSRS). A systematic study on reference organic dyes was primarily carried out to evaluate the suitability of the method and to estimate the strengths and limitations of the spectrum reconstruction process. The method was then applied to the noninvasive identification of madder on ancient dyed silk textiles such as an altar table cloth and a manutergium attributed to the Egyptian artistic textile production of the 10th–11th Century A.D. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
120.
Costanza Miliani Alessia Daveri Lin Spaabaek Aldo Romani Valentina Manuali Antonio Sgamellotti Brunetto Giovanni Brunetti 《Applied Physics A: Materials Science & Processing》2010,100(3):703-711
The present paper reports on the study of the development of whitish opacity in pink paints in encaustic mummy portraits.
Non-invasive measurements carried out on two encaustic portraits belonging to the Ny Carlsberg Glyptotek, Copenhagen, by reflectance
FTIR and UV–vis fluorescence have shown that the areas prone to the bleaching phenomenon had been painted with melted beeswax
and an anthraquinone vegetal lake mixed with calcium sulphate hemihydrate and dihydrate. The hypothesis that the bleaching
disease was neither related to a degradation of the dyes nor to an alteration of the wax but rather to a dehydration–hydration
reaction of the CaSO4–H2O system, has been corroborated by the analyses of two microsamples from the bleached areas and ascertained by accelerated
ageing experiments on encaustic models. 相似文献