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41.
Dra Lakk-Bogth Natalija Pantalon Juraj Bashdar I. Meena Berislav Peri Sreko I. Kirin Jzsef Kaizer 《Molecules (Basel, Switzerland)》2021,26(11)
Heme and nonheme-type flavone synthase enzymes, FS I and FS II are responsible for the synthesis of flavones, which play an important role in various biological processes, and have a wide range of biomedicinal properties including antitumor, antimalarial, and antioxidant activities. To get more insight into the mechanism of this curious enzyme reaction, nonheme structural and functional models were carried out by the use of mononuclear iron, [FeII(CDA-BPA*)]2+ (6) [CDA-BPA = N,N,N’,N’-tetrakis-(2-pyridylmethyl)-cyclohexanediamine], [FeII(CDA-BQA*)]2+ (5) [CDA-BQA = N,N,N’,N’-tetrakis-(2-quinolilmethyl)-cyclohexanediamine], [FeII(Bn-TPEN)(CH3CN)]2+ (3) [Bn-TPEN = N-benzyl-N,N’,N’-tris(2-pyridylmethyl)-1,2-diaminoethane], [FeIV(O)(Bn-TPEN)]2+ (9), and manganese, [MnII(N4Py*)(CH3CN)]2+ (2) [N4Py* = N,N-bis(2-pyridylmethyl)-1,2-di(2-pyridyl)ethylamine)], [MnII(Bn-TPEN)(CH3CN)]2+ (4) complexes as catalysts, where the possible reactive intermediates, high-valent FeIV(O) and MnIV(O) are known and well characterised. The results of the catalytic and stoichiometric reactions showed that the ligand framework and the nature of the metal cofactor significantly influenced the reactivity of the catalyst and its intermediate. Comparing the reactions of [FeIV(O)(Bn-TPEN)]2+ (9) and [MnIV(O)(Bn-TPEN)]2+ (10) towards flavanone under the same conditions, a 3.5-fold difference in reaction rate was observed in favor of iron, and this value is three orders of magnitude higher than was observed for the previously published [FeIV(O)(N2Py2Q*)]2+ [N,N-bis(2-quinolylmethyl)-1,2-di(2-pyridyl)ethylamine] species. 相似文献
42.
Chong-Qing Wang Xin Chen Jun-Hang Jiang Hui Tang Kong-Kai Zhu You-Jun Zhou Can-Hui Zheng Ju Zhu 《中国化学快报》2015,26(6):793-796
The benzyl-substituted flavone compounds are rare in nature, while some of which have interesting biological activities. The total synthesis of benzyl-substituted flavone derivatives via the acidic rearrangement of benzyl groups in flavone benzyl ethers, and the complicated regioselectivity of the rearrangement were reported. The regioselectivity was proposed to be determined by the steric hindrance as well as the ease of electrophilic substitution reaction for benzyl cations at different positions of corresponding debenzylated flavone compounds. 相似文献
43.
The title compound, (2R,3R)-3,5,7-trihydroxyflavanone 3-acetate, is a flavanonol derivative which was first isolated from Myoporum bontioides A. Gray and characterized by MS, NMR and CD spectra. In addition, the structure was determined by X-ray single-crystal diffraction analysis. It crystallizes in the triclinic lattice, space group P21 with a = 10.686(3), b = 6.862(2), c = 11.267(3) , β = 107.46(1), V = 788.3(4) 3, Z = 2, C17H16O7, Mr = 332.30, Dc = 1.400 g/cm3, μ(MoKα) = 0.110 mm-1, F(000) = 348, the final R = 0.0283 and wR = 0.0826 for 3428 independent reflections (Rint = 0.017) and 1500 observed ones (I > 2σ(I)). The structure consists of one flavone and one water molecule. The flavone molecules form a 1D column by the p…π stacking interactions and C–H…O hydrogen bonds. The weak intermolecular/intermolecular O–H…O hydrogen bonds observed in the crystal give further rise to a complicated network structure. Primary bioassay showed that the title compound has high inhibitory activity against Magnaporthe grisea with the EC50 values of 199.41 μg/mL. 相似文献
44.
MA Olszewska 《Journal of separation science》2012,35(17):2174-2183
An HPLC method of high resolution has been developed and validated for the simultaneous determination of ten prominent flavonoid aglycones in plant materials using a fused‐core C18‐silica column (Ascentis® Express, 4.6 mm × 150 mm, 2.7 μm). The separation was accomplished with an acetonitrile‐tetrahydrofuran gradient elution at a flow rate of 1 mL/min and temperature of 30°C. UV spectrophotometric detection was employed at 370 nm for flavonols (quercetin [QU], myricetin [MY], isorhamnetin [IS], kaempferol [KA], sexangularetin [SX], and limocitrin [LM]) and 340 nm for flavones (apigenin [AP], acacetin [AC], chrysoeriol [CH], and luteolin [LU]). The high resolution of critical pairs QU/LU (10.50), QU/CH (3.40), AP/CH (2.51), SX/LM (2.30), and IS/KA (2.70) was achieved within 30.3 min. The observed column back pressure was less than 4300 psi, thus acceptable for conventional HPLC equipment. The method was sensitive enough having LODs of 0.115–0.525 ng and good linearity (r > 0.9999) over the test range. The precision values, expressed as RSD values, were <7.5%, and the accuracy was in the range of 95.3–100.2% for all analytes except MY (73.8%). The method was successfully employed for the determination of flavonoids in several medicinal plants, such as Ginkgo biloba, Betula pendula, and a variety of Sorbus species. 相似文献
45.
基于巯基硅胶与单取代-6A-烯丙氨基-β-环糊精的巯基-烯点击化学反应,制备了β-环糊精(Click TE-CD)共价键合固定相。元素分析结果表明β-环糊精被成功键合到硅胶表面。以黄酮苷类化合物为模型,考察了Click TE-CD固定相在亲水、反相和超临界流体色谱等分离模式下的色谱保留行为。黄酮苷类化合物保留时间随流动相中乙腈含量的变化呈现典型的U型曲线,表明Click TE-CD固定相具有亲水/反相的双重保留特性。应用几何学方法测得Click TE-CD固定相在反相/亲水、亲水/超临界、反相/超临界混合模式下的正交性分别为69.8%、50.8%、50.8%。对比复杂中药样品降香提取物在反相、亲水、超临界等模式下的分离情况,结果表明Click TE-CD固定相在分离中药复杂样品方面具有极大潜力,可以在一根色谱柱上通过分离模式的改变,实现二维液相色谱的分离。Click TE-CD固定相不同分离模式的分离性能和较好的正交性表明该固定相具有在液相色谱方法发展和二维液相色谱分离方面应用的潜力。 相似文献
46.
47.
Studies on Triterpenoids and Flavones in Glycyrrhiza uralensis Fisch. By HPLC-ESI-MSn and FT-ICR-MSn
应用高效液相色谱质谱联用方法(HPLC-ESI-MSn)研究了甘草提取物中的七种化合物,四种三萜类化合物和三种黄酮类化合物。通过多极串联质谱(ESI-MSn)和多极串联傅里叶变换回旋共振质谱(FT-ICR-MSn)法研究了它们的碎裂规律。通过比较保留时间和质谱数据对上述七种化合物进行了归属,并阐述了其可能的质谱裂解途径。以上结果显示ESI-MSn和FT-ICR-MSn是非常有效的分析三萜类化合物和黄酮类化合物结构的工具。 相似文献
48.
49.
50.
Kowit Hengphasatporn Benyapa Kaewmalai Somruedee Jansongsaeng Vishnu Nayak Badavath Thanaphon Saelee Thamonwan Chokmahasarn Tanatorn Khotavivattana Yasuteru Shigeta Thanyada Rungrotmongkol Siwaporn Boonyasuppayakorn 《Molecules (Basel, Switzerland)》2021,26(22)
A flavonoid is a versatile core structure with various cellular, immunological, and pharmacological effects. Recently, flavones have shown anti-dengue activities by interfering with viral translation and replication. However, the molecular target is still elusive. Here we chemically modified apigenin by adding an alkyne moiety into the B-ring hydroxyl group. The alkyne serves as a chemical tag for the alkyne-azide cycloaddition reaction for subcellular visualization. The compound located at the perinuclear region at 1 and 6 h after infection. Interestingly, the compound signal started shifting to vesicle-like structures at 6 h and accumulated at 24 and 48 h after infection. Moreover, the compound treatment in dengue-infected cells showed that the compound restricted the viral protein inside the vesicles, especially at 48 h. As a result, the dengue envelope proteins spread throughout the cells. The alkyne-tagged apigenin showed a more potent efficacy at the EC50 of 2.36 ± 0.22, and 10.55 ± 3.37 µM, respectively, while the cytotoxicities were similar to the original apigenin at the CC50 of 70.34 ± 11.79, and 82.82 ± 11.68 µM, respectively. Molecular docking confirmed the apigenin binding to the previously reported target, ribosomal protein S9, at two binding sites. The network analysis, homopharma, and molecular docking revealed that the estrogen receptor 1 and viral NS1 were potential targets at the late infection stage. The interactions could attenuate dengue productivity by interfering with viral translation and suppressing the viral proteins from trafficking to the cell surface. 相似文献