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排序方式: 共有193条查询结果,搜索用时 232 毫秒
81.
Frey AS Cloke FG Hitchcock PB Day IJ Green JC Aitken G 《Journal of the American Chemical Society》2008,130(42):13816-13817
The stoichiometric reaction of 1 equiv of CO with [(U(eta-C8H6{SiiPr3-1,4}2)(eta-Cp*)] affords the linear diuranium ynediolate complex [(U(eta-C8H6{SiiPr3-1,4}2)(eta-Cp*)]2(mu-eta1:eta1-C2O2) which does not react with further CO to give the deltate derivative [(U(eta-C8H6{SiiPr3-1,4}2)(eta-Cp*)]2(mu-eta1:eta2-C3O3). Spectroscopic and computational studies suggest a plausible mechanism for the formation of the deltate complex, in which a "zig-zag" diuranium ynediolate species is the key intermediate. 相似文献
82.
Hutton BW MacIntosh F Ellis D Herisse F Macgregor SA McKay D Petrie-Armstrong V Rosair GM Perekalin DS Tricas H Welch AJ 《Chemical communications (Cambridge, England)》2008,(42):5345-5347
The reduction and subsequent oxidation of meta-carboranes containing bulky groups attached to the cage C atoms affords sterically-crowded ortho-carboranes with unprecedentedly long C-C connectivities. 相似文献
83.
Banerjee S Sen S Mitra S Rizzoli C Rosair GM 《Dalton transactions (Cambridge, England : 2003)》2008,(13):1783-1786
The aerial oxidation of cobalt(II) salt, in a methanolic solution, containing a hydrazone ligand, (E)-N'-(4-oxo-4-phenylbutan-2-ylidene)benzohydrazide (condensation product of benzoyl acetone and benzhydrazide, LH2) leads to the coupling of two such ligand units through the formation of a rather long C-C bond [1.601(6) A] giving rise to a dinuclear Co (III) hydrazone complex, [Co2(L)2(L')(].0.25H2O (L' = C-C coupled hydrazone ligand). The structure of the complex has been determined by X-ray crystallography and IR, UV-Vis spectroscopy and elemental analysis have characterized the complex. 相似文献
84.
Marco Brito-Arias Manuel Tapia-Albarrán Itzia Padilla-Martínez Francisco Martínez-Martínez Georgina Espinosa Elies Molins Enrique Espinosa 《Journal of chemical crystallography》1999,29(7):759-763
Several 9-(2-R phenyl)xanthenediones have been synthesized and the x-ray diffraction structure for the 2-methylphenyl derivative (4b) has been determined. This compound crystallizes in the monoclinic system, space group P21/n, with a = 11.729 (3), b = 9.674 (3), c = 14.628 (4) Å, and = 106.30°. It presents a partially hydrogenated xanthene system in distorted boat conformation for the heterocyclic central ring, and an almost ideal envelope conformation for the outer rings. The aromatic substituent at the ninth position is at 84° in angle with the xanthene system. 相似文献
85.
Alexandre Gonçalves Dal Bó Yasmine Miguel Serafini Micheletto Fernando Carlos Giacomelli Georgina Lopez Maria Julia Recco Sartor Jamal Rafique 《Liquid crystals》2016,43(3):292-304
This article describes the synthesis and liquid crystal properties of new compounds that are derived from gallic acid. All the compounds were characterised by 1H and 13C nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR), Infrared spectroscopy (IR) and Elemental analysis (CHN). The mesophases of these compounds were characterised using polarising optical microscopy (POM), differential scanning calorimetry (DSC) and SAXS measurements. The morphology of the surface of the films was investigated using atomic force microscopy (AFM). Compounds 9 and 13, which remain in a supercooled state until room temperature, do not exhibit liquid crystalline behaviour. The other compounds (i.e., 5, 7 and 8) self-assemble into tubular supramolecular architectures generating hexagonal columnar (Colh) mesophases, which was confirmed by SAXS measurements. 相似文献
86.
Nadiia Kovalenko Dr. Jonathan A. Swain Georgina K. Howard Yann O. Hermant Dr. Alan J. Cameron Dr. Louise A. Stubbing Prof. Paul W. R. Harris Prof. Margaret A. Brimble 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(70):e202202554
In the current global crisis of antimicrobial resistance, antimicrobial peptides represent a promising source of alternative antibiotics. Recently discovered cadaside B, a novel calcium-dependent antibiotic, exhibits potent antimicrobial activity towards Gram-positive pathogens including multi-drug resistant strains. These properties, coupled with a novel structure, non-cytotoxicity, and low likelihood of developing resistance render cadaside B an important synthetic target. Herein, a synthetic strategy towards cadaside B is reported with the key steps involving on-resin depsipeptide bond formation and solution-phase macrolactamization. Good agreement of the synthetic cadaside B MS/MS fragmentation pattern was observed with the natural product, but a different 1H NMR spectrum and absence of antimicrobial activity suggest an undetected epimerization event took place during the synthesis. Herein the findings of our synthetic journey and suggestions for future directions are presented. 相似文献
87.
Marco A. Landey-Álvarez Georgina Pina-Luis Marisela Martínez-Quiroz Milagros Aguilar-Martínez José Elías-García 《Supramolecular chemistry》2016,28(11-12):892-906
A series of novel naphthalimide–aminobenzamide (NAPIM-2ABZ) dyads 3 connected by different length polymethylene chains were synthesized and studied as fluorescent supramolecular receptors in metal ion binding. The photophysical properties were evaluated and compared with separated chromophores. The electronic absorption spectra of dyads 3 showed no interaction between chromophores in the ground state. The fluorescence quantum yields were lower in dyads 3 in comparison with N-propyl-2-aminobenzamide (8). The fluorescence quenching is attributed to a PET mechanism between fluorophores (from 2ABZ to NAPIM), which is dependent on the polymethylene chain length. In metal binding study was found a response towards transition metal ions such as Hg(II), Cu(II), Zn(II) and Ni(II). Dyad 3b presented selectivity towards Cu(II). The UV-vis, IR and 1H-NMR studies demonstrated the interaction with 2ABZ moiety in the ground state, and interestingly dyads with shorter polymethylene chains 3a (n = 0), 3b (n = 1) and 3c (n = 2) exhibited an OFF/ON fluorescence behaviour due to the PET inhibition and the quenching of 2ABZ fluorescence. Dyads 3d (n = 4) and 3e (n = 6) presented opposite response ON/OFF in the complex with metal ions evidencing the absence of PET in these dyads. 相似文献
88.
Giang Huong Nguyen Thomas S. Dexheimer Andrew S. Rosenthal Wai Kit Chu Dharmendra Kumar Singh Georgina Mosedale Csanád Z. Bachrati Lena Schultz Masaaki Sakurai Pavel Savitsky Mika Abu Peter J. McHugh Vilhelm A. Bohr Curtis C. Harris Ajit Jadhav Opher Gileadi David J. Maloney Anton Simeonov Ian D. Hickson 《Chemistry & biology》2013,20(1):55-62
89.
90.
Bernadette S. Creaven Michael Devereux Agnieszka Foltyn Siobhán McClean Georgina Rosair Venkat Reddy Thangella Maureen Walsh 《Polyhedron》2010
The condensation of 4-amino-1,2,4-triazole with N-substituted-3-formyl-4-hydroxyquinolin-2-(1H)-one derivatives has lead to the synthesis of a new series of quinolin-2(1H)-one-triazole derived Schiff base ligands (1–3). Cu(II) and Zn(II) complexes (1a–3a and 1b–3b, respectively) of these ligands were also prepared. The complexes were characterised by standard techniques and for two of the complexes X-ray crystallography confirmed that the geometry at the metal centre was octahedral in both cases and that the Schiff base acted as a bidentate ligand coordinating to the metal(II) ion through the deprotonated oxygen and azomethine nitrogen atoms. All of the compounds were investigated for their antimicrobial activities against a fungal strain, Candida albicans, and against Gram-positive and Gram-negative bacteria. The compounds were found to be active against C. albicans but inactive against Staphylococcusaureus and Escherichia coli. 相似文献