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排序方式: 共有93条查询结果,搜索用时 31 毫秒
81.
We investigate strong stability preserving(SSP)implicit-explicit(IMEX)methods for par-titioned systems of differential equations with stiff and nonstiff subsyst... 相似文献
82.
An almost alternating stereoregular copolymer can be obtained by copolymerizing ethylene and styrene with the catalyst ethylenebis(1-indenyl)zirconium dichloride activated by methylaluminoxane at −25°C. The regular microstructure pointed out by the NMR spectrum allows the copolymer to crystallize as shown by calorimetric and X-ray diffraction measurements. 相似文献
83.
Iminosugar‐Cyclopeptoid Conjugates Raise Multivalent Effect in Glycosidase Inhibition at Unprecedented High Levels
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Dr. Mathieu L. Lepage Jérémy P. Schneider Dr. Anne Bodlenner Alessandra Meli Prof. Francesco De Riccardis Dr. Marjorie Schmitt Prof. Céline Tarnus Dr. Nha‐Thi Nguyen‐Huynh Dr. Yannis‐Nicolas Francois Dr. Emmanuelle Leize‐Wagner Dr. Catherine Birck Alexandra Cousido‐Siah Dr. Alberto Podjarny Prof. Irene Izzo Prof. Philippe Compain 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5151-5155
A series of cyclopeptoid‐based iminosugar clusters has been evaluated to finely probe the ligand content‐dependent increase in α‐mannosidase inhibition. This study led to the largest binding enhancement ever reported for an enzyme inhibitor (up to 4700‐fold on a valency‐corrected basis), which represents a substantial advance over the multivalent glycosidase inhibitors previously reported. Electron microscopy imaging and analytical data support, for the best multivalent effects, the formation of a strong chelate complex in which two mannosidase molecules are cross‐linked by one inhibitor. 相似文献
84.
Dr. Giovanni Pierri Dr. Alessandro Landi Dr. Eleonora Macedi Prof. Irene Izzo Prof. Francesco De Riccardis Prof. Robert E. Dinnebier Prof. Consiglia Tedesco 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(63):14320-14323
Cyclic peptoids are macrocyclic N-substituted oligoglycines, with remarkable structural, chemical and physical properties. The gas adsorption properties of a permanently porous hexameric cyclopeptoid decorated with four propargyl and two methoxyethyl side chains were monitored by in situ X-ray powder diffraction (XRPD). High-resolution XRPD data together with Rietveld and density functional based tight binding (DFTB) method allowed us to locate propyne guest molecules inside the host channels, even though the powder sample contains more than one phase. We were able to characterize the host-guest interactions, providing useful information on the host recognition sites and discuss host adaptiveness and host–guest chemical affinity in comparison with analogous compounds. 相似文献
85.
Luigi Castaldo Luana Izzo Stefania De Pascale Alfonso Narvez Yelko Rodriguez-Carrasco Alberto Ritieni 《Molecules (Basel, Switzerland)》2021,26(7)
Fennel (Foeniculum vulgare Mill.) waste contains a broad range of bioactive molecules, including polyphenols, which have poor bioaccessibility during gastrointestinal digestion. This work aimed to investigate the bioaccessibility of total phenolic compounds and the antioxidant capacity during simulated gastrointestinal digestion using two nutraceutical formulations based on non-acid-resistant (NAR) and acid-resistant (AR) capsules containing aqueous-based extracts from fennel waste. Moreover, to obtain a comprehensive investigation of the polyphenolic constituents of the fennel waste extract, a high-resolution mass spectrometry (Q-Orbitrap) analysis was performed. Notably, chlorogenic acids, such as 4-caffeoylquinic acid and 3,4-dicaffeoylquinic acid, were the most detected compounds found in assayed samples (1.949 and 0.490 mg/g, respectively). After in vitro gastrointestinal digestion, the extract contained in AR capsules displayed higher bioaccessibility in both the duodenal and colonic stages (1.96 and 5.19 mg GAE/g, respectively) than NAR capsules (1.72 and 3.50 mg GAE/g, respectively), suggesting that the acidic gastric conditions negatively affected the polyphenol compounds released from the NAR capsules. Therefore, the aqueous extract of fennel waste could be proposed as an innovative and easily available source of dietary polyphenols. Furthermore, the use of an AR capsule could improve the polyphenol bioaccessibility and can be proposed as a nutraceutical formulation. 相似文献
86.
Dr. Mathieu L. Lepage Dr. Jérémy P. Schneider Dr. Anne Bodlenner Dr. André Mitschler Dr. Alessandra Meli Prof. Irene Izzo Dr. H. Ariel Alvarez Dr. Alberto Podjarny Prof. Philippe Compain 《Angewandte Chemie (International ed. in English)》2018,57(27):8002-8006
Multivalent design of glycosidase inhibitors is a promising strategy for the treatment of diseases involving enzymatic hydrolysis of glycosidic bonds in carbohydrates. An essential prerequisite for successful applications is the atomic‐level understanding of how outstanding binding enhancement occurs with multivalent inhibitors. Herein we report the first high‐resolution crystal structures of the Jack bean α‐mannosidase (JBα‐man) in apo and inhibited states. The three‐dimensional structure of JBα‐man in complex with the multimeric cyclopeptoid‐based inhibitor displaying the largest binding enhancements reported so far provides decisive insight into the molecular mechanisms underlying multivalent effects in glycosidase inhibition. 相似文献
87.
Solid‐State Conformational Flexibility at Work: Zipping and Unzipping within a Cyclic Peptoid Single Crystal
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Dr. Alessandra Meli Dr. Eleonora Macedi Prof. Francesco De Riccardis Dr. Vincent J. Smith Prof. Leonard J. Barbour Prof. Irene Izzo Dr. Consiglia Tedesco 《Angewandte Chemie (International ed. in English)》2016,55(15):4679-4682
A peptidomimetic compound undergoes a reversible single‐crystal‐to‐single‐crystal transformation upon guest release/uptake with the transformation involving a drastic conformational change. The extensive and reversible alteration in the solid state is connected to the formation of an unprecedented “CH–π zipper” which can reversibly open and close (through the formation of CH–π interactions), thus allowing for guest sensing. 相似文献
88.
Antonio Fiorentino Marina DellaGreca Annunziata Golino Angelina Izzo 《Tetrahedron》2006,62(38):8952-8958
Implementing the phytochemical study of the weed Amaranthus retroflexus, four new sesquiterpene glucosides were isolated from the methanolic extract of the plant. The structures of these metabolites are determined on the basis of the mass spectrometry, and 1D and 2D NMR spectroscopies (DQ-COSY, TOCSY, HSQC, HSQC-TOCSY, HMBC, and NOESY). Two compounds are characterized by a new aglycone and differed from the site of glucosylation. The other two compounds are dimeric diastereoisomers.All the glucoside sesquiterpenes were tested on the wild species Taraxacum officinale to evaluate the role of this weed in the habitat and on the seed of A. retroflexus to verify the potential autotoxic effect of the plant. 相似文献
89.
Raman R Jarboe TR Nelson BA Izzo VA O'Neill RG Redd AJ Smith RJ 《Physical review letters》2003,90(7):075005
The first successful results on the transfer of a coaxial helicity injection (CHI) produced discharge to inductive operation are reported. CHI-assisted plasma startup is more robust than inductive only operation. After hand off for inductive operation, the initial 90 kA of CHI-produced current drops to 40 kA, then ramps up to 170 kA, using only 30 mV s, more than 30% higher than that produced by induction alone. These significant performance enhancing results were obtained on the HIT-II spherical torus experiment (major/minor radius of 0.3/0.2 m). 相似文献
90.
Maulucci N Chini MG Micco SD Izzo I Cafaro E Russo A Gallinari P Paolini C Nardi MC Casapullo A Riccio R Bifulco G Riccardis FD 《Journal of the American Chemical Society》2007,129(10):3007-3012
Azumamide E, a cyclotetrapeptide isolated from the sponge Mycale izuensis, is the most powerful carboxylic acid containing natural histone deacetylase (HDAC) inhibitor known to date. In this paper, we describe design and synthesis of two stereochemical variants of the natural product. These compounds have allowed us to clarify the influence of side chain topology on the HDAC-inhibitory activity. The present contribution also reveals the identity of the recognition pattern between azumamides and the histone deacetylase-like protein (HDLP) model receptor and reports the azumamide E unprecedented isoform selectivity on histone deacetylases class subtypes. From the present studies, a plausible model for the interaction of azumamides with the receptor binding pocket is derived, providing a framework for the rational design of new cyclotetrapeptide-based HDAC inhibitors as antitumor agents. 相似文献