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71.
Nicolaos Doitsides Demetrios Mentzafos Sophia Mitkidou Aristides Terzis Julia Stephanidou-Stephanatou 《合成通讯》2013,43(9):1411-1418
Treatment of the readily available l-methylpyrano[3,4-b]indol-3-one with primary aromatic amines leads directly to the formation of Schiff bases of the indole alkaloid Salvadoricine (2-acetyl-3-methyl-indole). 相似文献
72.
Yanina V. Burgart Galina F. Makhaeva Olga P. Krasnykh Sophia S. Borisevich Natalia A. Agafonova Nadezhda V. Kovaleva Natalia P. Boltneva Elena V. Rudakova Evgeny V. Shchegolkov Galina A. Triandafilova Denis A. Gazizov Olga G. Serebryakova Maria V. Ulitko Sergey L. Khursan Victor I. Saloutin Rudy J. Richardson 《Molecules (Basel, Switzerland)》2022,27(22)
One of the powerful antioxidants used clinically is Edaravone (EDA). We synthesized a series of new EDA analogs, 4-aminopyrazol-5-ol hydrochlorides, including polyfluoroalkyl derivatives, via the reduction of 4-hydroxyiminopyrazol-5-ones. The primary antioxidant activity of the compounds in comparison with EDA was investigated in vitro using ABTS, FRAP, and ORAC tests. In all tests, 4-Amino-3-pyrazol-5-ols were effective. The lead compound, 4-amino-3-methyl-1-phenylpyrazol-5-ol hydrochloride (APH), showed the following activities: ABTS, 0.93 TEAC; FRAP, 0.98 TE; and ORAC, 4.39 TE. APH and its NH-analog were not cytotoxic against cultured normal human fibroblasts even at 100 μM, in contrast to EDA. According to QM calculations, 4-aminopyrazolols were characterized by lower gaps, IP, and η compared to 4-hydroxyiminopyrazol-5-ones, consistent with their higher antioxidant activities in ABTS and FRAP tests, realized by the SET mechanism. The radical-scavenging action evaluated in the ORAC test occurred by the HAT mechanism through OH bond breaking in all compounds, directly dependent on the dissociation energy of the OH bond. All the studied compounds demonstrated the absence of anticholinesterase activity and moderate inhibition of CES by some 4-aminopyrazolols. Thus, the lead compound APH was found to be a good antioxidant with the potential to be developed as a novel therapeutic drug candidate in the treatment of diseases associated with oxidative stress. 相似文献
73.
Sophia Lipstman Sankar Muniappan Israel Goldberg 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(7):o371-o373
Molecules of the title compound, porphyrin‐54,104,154,204‐tetrabenzoic acid, C48H30N4O8, lie on sites of 2/m symmetry in the space group Cmca. The crystals consist of doubly interwoven two‐dimensional supramolecular arrays sustained by multiple (COOH)2 cyclic dimeric hydrogen bonds, each molecule of the porphyrintetrabenzoic acid coordinating to four neighbouring species. This structure, which encloses substantial spaces occupied by disordered dimethylformamide solvent molecules, represents yet another supramolecular isomer of this porphyrin. 相似文献
74.
David Elbaz Sophia Buhbut Benjamin Zeev Kupfer Arie Zaban Zeev Zalevsky 《Optics Communications》2012,285(10-11):2746-2749
In this paper we present a new type of optical fiber aiming to radially polarize the electrical field. This special device is composed of a tapered fiber having a classical core while on top of its external surface, radially oriented nanorods are disposed. The tails of the propagated wave are interacting with those radially oriented nanorods. This interaction performs the polarization of the propagated mode into a radial polarization. 相似文献
75.
Dr. Heiko Geisler Dr. Sophia Harringer Dominik Wenisch Richard Urban Dr. Michael A. Jakupec Dr. Wolfgang Kandioller Prof. Dr. Dr. Bernhard K. Keppler 《ChemistryOpen》2022,11(7):e202200019
The cytotoxicities of seven dimeric metal species of the general formula [M(arene)Cl2]2, commonly used as precursors for complex synthesis and deemed biologically inactive, are investigated in seven commonly employed human cancer cell lines. Four of these complexes featured a ruthenium(II) core, where p-cymene, toluene, benzene and indane were used as arenes. Furthermore, the osmium(II) p-cymene dimer, as well as the Cp* dimers of rhodium(III) and its heavier analogue iridium(III) were included in this work (Cp*=1,2,3,4,5-pentamethylcyclopentadienide). While the cytotoxic potencies of the ruthenium(II) and osmium(II) dimers are very low (or not even detectable at applicable concentrations), surprising activity, especially in cells from ovarian malignancies (with one or two-digit micromolar IC50 values), have been found for the rhodium(III) and iridium(III) representatives. This publication is aimed at all researchers using synthetic procedures based on functionalization of these dimeric starting materials to rationalize changes in biological properties, especially cytotoxicity in cancer cells. 相似文献
76.
Demetrius G. Themelis Sophia C. Karastogianni Paraskevas D. Tzanavaras 《Analytica chimica acta》2009,632(1):93-116
A highly selective sequential injection (SI) method for the automated determination of weak-acid-dissociable cyanides is reported. The analytical procedure is based on the on-line reaction of the analyte with ninhydrin in carbonate medium to form a coloured product (λmax = 510 nm). Cyanides are removed from sample matrix by acidification through a gas-diffusion step incorporated in the SI manifold. The effect of instrumental and chemical variables was studied. By adopting an on-line standard addition protocol, the sensitivity of the proposed method was enhanced drastically, without affecting the determination range. The assay was validated in terms of linearity (up to 200 μg L−1), limit of detection (cL = 2.5 μg L−1), limit of quantitation (cQ = 7.5 μg L−1), precision (sr < 2.5% at 100 μg L−1) and selectivity. High tolerance against critical species such as sulfides and thiocyanates was achieved. The applicability of the method was demonstrated by analyzing tap and mineral water samples at levels below the limits established by international E.U. and U.S. organizations. The percent recoveries were satisfactory in all cases, ranging between 94.2 and 103.6%. 相似文献
77.
Sophia S. Michaelidou 《Tetrahedron》2010,66(3):685-3845
Anthranilonitrile 3a, 4,5-dimethoxyanthranilonitrile 3b and 5-nitroanthranilonitrile 3c, react with paraformaldehyde, KCN and ZnCl2 in acetic acid under acid catalysis (H2SO4) in a sealed tube at ca. 55 °C to give the corresponding 2-(cyanomethylamino)benzonitriles 4a-c in 96, 86 and 57% yields, respectively. Thorpe-Ziegler cyclisation of the N-unprotected 2-(cyanomethylamino)benzonitriles 4a-c with K2CO3 in EtOH at elevated temperatures and pressures using either microwave heating or conventional heating in a sealed tube gives 3-amino, 3-amino-5,6-dimethoxy, and 3-amino-5-nitroindole-2-carbonitriles 2a-c in moderate to good yields. All new compounds are fully characterised. 相似文献
78.
The Bowman-Birk inhibitors (BBIs) are a family of proteins that share a canonical loop structure whose presence in a conserved conformation is linked to their inhibitory activity. We study the conformational properties of the canonical loop using a graph theoretical approach as implemented in the floppy inclusions and rigid substructure topography (FIRST). We find that the canonical loop is an independent rigid cluster in the natural inhibitors. We have further used this technique to identify residues that play an important role in the structural rigidity of the protein by quantifying their contribution to the overall rigidity of the inhibitor. We find that the conserved elements among the natural and synthetic peptides are the ones that contribute the most to rigidity, even if they are located far from the active site, as rigidity effects are nonlinear and hence nonlocal. The results help to elucidate why certain mutations in the loop of the BBI produce peptides that fail to have the designed inhibitory activity. 相似文献
79.
Gullick J Taylor S Ryan D McMorn P Coogan M Bethell D Bulman Page PC Hancock FE King F Hutchings GJ 《Chemical communications (Cambridge, England)》2003,(22):2808-2809
During the aziridination of styrene using copper bis(oxazoline) complexes the ee increases with conversion due to further reactions of the product. 相似文献
80.
Sankar Muniappan Sophia Liptsman Israel Goldberg 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(4):m140-m143
Tetrakis(4‐methoxycarbonylphenyl)porphyrin, or tetramethyl 4,4′,4′′,4′′′‐porphyrin‐5,10,15,20‐tetrabenzoate, crystallizes as a nitrobenzene 1.9‐solvate, C52H38N4O8·1.9C6H5NO2, (I). The solvent molecules are contained in extended channels which propagate through the host lattice between parallel screw/glide‐related columns of offset‐stacked porphyrin entities. Side packing of these columns involves π–π interactions between the methoxycarbonylphenyl residues. Molecules of the porphyrin host lie on crystallographic inversion centres. The zinc(II)–pyridine derivative pyridine(tetramethyl 4,4′,4′′,4′′′‐porphyrin‐5,10,15,20‐tetrabenzoato)zinc(II), [Zn(C52H36N4O8)(C5H5N)], (II), is a square‐pyramidal five‐coordinate complex with pyridine as an apical ligand, which crystallizes as a chloroform–pyridine solvate. The metalloporphyrin–pyridine units form an open layered arrangement, occluding the non‐coordinated solvent moieties within the intralayer interporphyrin voids. Within such arrays, the host porphyrin molecules are in contact with one another through the peripheral methoxycarbonyl substituents. The crystal packing consists of a bilayered arrangement of inversion‐related porphyrin layers, with the axial ligands mutually penetrating into the voids of neighbouring arrays and tight offset stacking of these bilayers. 相似文献