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101.
Structural determination and DPPH radical-scavenging activity of two acylated flavonoid tetraglycosides in oolong tea (Camellia sinensis) 总被引:1,自引:0,他引:1
Two major acylated flavonoid tetraglycosides were isolated from the methanol extract of oolong tea. Their structures were elucidated by spectroscopic methods as quercetin 3-O-[2(G)-(E)-coumaroyl-3(G)-O-beta-D-glucosyl-3(R)-O-beta-D-glucosylrutinoside] (1) and kaempferol 3-O-[2(G)-(E)-coumaroyl-3(G)-O-beta-D-glucosyl-3(R)-O-beta-D-glucosylrutinoside] (2). Compounds 1 and 2 exhibited scavenging activity against DPPH radical with EC(50) values of 30.5 and 487.2 microM, respectively. 相似文献
102.
Viola G Vedaldi D Dall'Acqua F Lampronti I Bianchi N Zuccato C Borgatti M Gambari R 《Journal of photochemistry and photobiology. B, Biology》2008,92(1):24-28
Psoralens, also known as furocoumarins, are a well-known class of photosensitizers largely used in the therapy of various skin disease. In this study we have evaluated the effects of crude pre-irradiated solutions of furocoumarins derivatives on (a) erythroid differentiation and apoptosis of human leukemic K562 cells and (b) hemoglobin synthesis in cultures of human erythroid progenitors derived from the peripheral blood. To prove the activity of a mixture of photoproducts generated by UVA irradiation of the three psoralen derivatives 5-methoxypsoralen (5-MOP) 8-methoxypsoralen (8-MOP), and angelicin (ANG), we employed the human leukemic K562 cell line and the two-phase liquid culture procedure for growing erythroid progenitors. The results obtained demonstrate that pre-irradiated solutions of psoralen derivatives significantly induce erythroid differentiation of K562 cells irrespective of the type of derivative used, suggesting that the active photoproduct(s) share a common structure. Interestingly, solutions of psoralens irradiated in anaerobic conditions do not exhibits erythroid inducing ability, indicating that the effect is mostly due to photooxidized psoralen products. In erythroid precursor cells, psoralens photolysis products stimulates at low concentrations an increase of hemoglobin A and hemoglobin F. Altogether, these data suggest that photoproducts of psoralen warrant further evaluation as potential therapeutic drugs in beta-thalassaemia and sickle cell anaemia. 相似文献
103.
104.
Giordano Lesma Alessandro Sacchetti Rouli Bai Giuseppe Basso Roberta Bortolozzi Ernest Hamel Alessandra Silvani Nadia Vaiana Giampietro Viola 《Molecular diversity》2014,18(2):357-373
A representative series of structural analogs of the antimitotic tripeptides hemiasterlins have been designed and synthesized, as potential inhibitors of tubulin polymerization. Relying also on a computational approach, we aimed to explore unknown extensive changes at the C-fragment, by incorporating the conformationally required double bond into five- and six-membered rings. Key steps of the synthetic strategy are a dynamic resolution affording the A-fragment in 97 % ee and the preparation of six new cyclic C fragments, all potentially able to interact with tubulin by means of H bonds. Unexpectedly, biological evaluation of these analogs did not provide evidences neither for cytotoxic effect nor for inhibition of tubulin polymerization. 相似文献
105.
106.
107.
Sonja Tragl Katharina Gibson Jochen Glaser Greta Heydenrych Gernot Frenking Viola Duppel Arndt Simon H.‐Jürgen Meyer 《无机化学与普通化学杂志》2008,634(15):2754-2760
Solid state metathesis reactions between cyanuric chloride and C–N–H or alkali metal–(B–)C–N compounds, respectively, were carried out in the temperature range between 150 °C to 500 °C, studying intermediate stages of reactions and targeting the formation of carbon nitride materials by elimination of HCl or alkali metal chlorides. Although cyanuric chloride was reacted with quite a number of different reaction partners such as melamine, cyanamide, lithium nitride, lithium or sodium carbodiimide, lithium nitridoborate or sodium dicyandiamide, always the same intermediate compounds appeared in the reactions mixtures. Colorless, needle‐shaped crystals of the tertiary amine N(C3N3Cl2)3 ( 1 ) were obtained at temperatures around 200–250 °C. Temperatures as high as 400 °C yielded yellow, plate‐like crystals of the heptazine compound C6N7Cl3 ( 2 ). At even higher temperatures, the reaction products were of poorer crystallinity, but evidence of the formation of another crystalline intermediate was given by X‐ray powder diffraction and electron diffraction experiments. This third intermediate is assumed to be a tertiary amine, quite similar to 1 , however, having heptazine ligands instead of triazine ligands and is assigned with the formula N(C6N7Cl2)3 ( 3 ). Theoretical calculations were performed for the structures and the vibrational spectra of 1 and 3 . Theoretical calculations and a structure refinement based of X‐ray powder diffraction data yielded a plausible structural model for compound 3 . 相似文献
108.
Order - For any triple given by a positive integer n, a finite group G, and a faithful representation V of G, one can describe a subspace arrangement whose intersection lattice is a generalized... 相似文献
109.
Tullio Viola 《Annali di Matematica Pura ed Applicata》1935,14(1):249-254
Sunto Si completa uno studio precedente, sulla rappresentazione piana dei sistemi lineari di complessi lineari, secondo il metodo
dualistico delMayor. 相似文献
110.
Ren‐Jye Lee Viola S. Y. Lee Jason T. C. Tzen Maw‐Rong Lee 《Rapid communications in mass spectrometry : RCM》2010,24(7):851-858
Liquid chromatography combined with multiple‐stage mass spectrometry (LC/MSn) was used to study the pathway of the release of gallic acid (GA) from epigallocatechin gallate (EGCG) in infusion of old oolong tea. The possibility of releasing GA from EGCG in old tea preparations was supported by an in vitro observation of GA degraded from EGCG under heating conditions mimicking the drying process. Negative electrospray ionization with the data‐dependent mode of MSn was used to study the formation pathway of GA in old oolong tea. The MSn data show that GA was released from the dimer of EGCG, not directly degraded from EGCG. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献