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1.
XPS and resistive studies on thin films of a copper(II)‐based coordination polymer deposited on functionalized interdigital electrodes 下载免费PDF全文
Michael Günthel Jörg Hübscher Rosemarie Dittrich Edwin Weber Yvonne Joseph Florian Mertens 《Journal of Polymer Science.Polymer Physics》2015,53(5):335-344
A symmetrical 2‐thiopyrimidine based molecule with an expanded π‐electron system is synthesized and used to form a self‐assembled monolayer (SAM) on gold surfaces. Utilizing chemical vapor deposition a monolayer of (3‐mercaptopropyl)triethoxysilane is formed on silicon dioxide substrates. Both of these SAM coated substrates are characterized by X‐ray photoelectron spectroscopy and the growth of a coordination polymer built up from 5,5′‐(ethyne‐1,2‐diyl)bis(2‐hydroxyacetophenone) and copper(II) on dual SAM coated transducers is studied. After the deposition procedure on interdigital electrodes the electrical properties of the polymer are investigated performing resistive measurements. A significant change of the resistance, which depends on the surrounding atmosphere, proves the sensing behavior of the synthesized coordination polymer. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 335–344 相似文献
2.
Arumugam Thangavel Marika Wieliczko Christopher Scarborough Birger Dittrich John Bacsa 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(11):936-943
In the crystal structure of the title homoleptic CrII complex, [Cr(CH3CN)6](C24H20B)2·CH3CN, the [Cr(CH3CN)6]2+ cation is a high‐spin d4 complex with strong static, rather than dynamic, Jahn–Teller distortion. The electron density of the cation was determined by single‐crystal X‐ray refinements using aspherical structure factors from wavefunction calculations. The detailed picture of the electronic density allowed us to assess the extent and directionality of the Jahn–Teller distortion of the CrII cation away from idealized octahedral symmetry. The topological analysis of the aspherical d‐electron density about the CrII cation showed that there are significant valence charge concentrations along the axial Cr—N axes. Likewise, there were significant valence charge depletions about the CrII cation along the equatorial Cr—N bonds. These charge concentrations are in accordance with a Jahn–Teller‐distorted six‐coordinate complex. 相似文献
3.
Stepwise Halide‐Triggered Double and Triple Catenation of Self‐Assembled Coordination Cages 下载免费PDF全文
Rongmei Zhu Jens Lübben Priv.‐Doz. Dr. Birger Dittrich Prof. Dr. Guido H. Clever 《Angewandte Chemie (International ed. in English)》2015,54(9):2796-2800
A simple self‐assembled [Pd2 L 4] coordination cage consisting of four carbazole‐based ligands was found to dimerize into the interpenetrated double cage [3 X@Pd4 L 8] upon the addition of 1.5 equivalents of halide anions (X=Cl?, Br?). The halide anions serve as templates, as they are sandwiched by four PdII cations and occupy the three pockets of the entangled cage structure. The subsequent addition of larger amounts of the same halide triggers another structural conversion, now yielding a triply catenated link structure in which each PdII node is trans‐coordinated by two pyridine donors and two halide ligands. This simple system demonstrates how molecular complexity can increase upon a gradual change of the relative concentrations of reaction partners that are able to serve different structural roles. 相似文献
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Matthias Dittrich Dr. Martin Heinze Christian Wölk Dr. Sergio S. Funari Prof. Dr. Bodo Dobner Prof. Dr. Helmuth Möhwald Prof. Dr. Gerald Brezesinski 《Chemphyschem》2011,12(12):2328-2337
Cationic liposome/DNA complexes can be used as nonviral vectors for direct delivery of DNA‐based biopharmaceuticals to damaged cells and tissues. To obtain more effective and safer liposome‐based gene transfection systems, two cationic lipids with identical head groups but different chain structures are investigated with respect to their in vitro gene‐transfer activity, their cell‐damaging characteristics, and their physicochemical properties. The gene‐transfer activities of the two lipids are very different. Differential scanning calorimetry and synchrotron small‐ and wide‐angle X‐ray scattering give valuable structural insight. A subgel‐like structure with high packing density and high phase‐transition temperature from gel to liquid‐crystalline state are found for lipid 7 (N′‐2‐[(2,6‐diamino‐1‐oxohexyl)amino]ethyl‐2,N‐bis(hexadecyl)propanediamide) containing two saturated chains. Additionally, an ordered head‐group lattice based on formation of a hydrogen‐bond network is present. In contrast, lipid 8 (N′‐2‐[(2,6‐diamino‐1‐oxohexyl)amino]ethyl‐2‐hexadecyl‐N‐[(9Z)‐octadec‐9‐enyl]propanediamide) with one unsaturated and one saturated chain shows a lower phase‐transition temperature and a reduced packing density. These properties enhance incorporation of the helper lipid cholesterol needed for gene transfection. Both lipids, either pure or in mixtures with cholesterol, form lamellar phases, which are preserved after addition of DNA. However, the system separates into phases containing DNA and phases without DNA. On increasing the temperature, DNA is released and only a lipid phase without intercalated DNA strands is observed. The conversion temperatures are very different in the two systems studied. The important parameter seems to be the charge density of the lipid membranes, which is a result of different solubility of cholesterol in the two lipid membranes. Therefore, different binding affinities of the DNA to the lipid mixtures are achieved. 相似文献
7.
Anatol P. Spork Stefan Koppermann Birger Dittrich Regine Herbst-Irmer Christian Ducho 《Tetrahedron: Asymmetry》2010,21(7):763-766
The reaction of protected uridine 5′-aldehydes with sulfur ylides has been reinvestigated. Further transformation of the resulting epoxide product provided a compound of which a single crystal for X-ray diffraction was obtained. As a consequence from the elucidated structure, the stereochemical configuration of the epoxide furnished by the sulfur ylide reaction was revised. Based on these results, an efficient synthesis of the core structure of the naturally occurring muraymycin and caprazamycin nucleoside antibiotics was developed. 相似文献
8.
Lamellarin K is a complex pyrrole natural product and member of the lamellarin family – a group of natural products known for their potent biological activities, such as, antiproliferative activity and inhibition of P-gp mediated drug efflux pumps. We herein describe the synthesis of the N-benzyl-des-D ring analogue of lamellarin K using a route that centres on an acyl-Claisen reaction to eventually prepare a highly-functionalised 1-aryl-4-methyl-1,4-diketone. Paal-Knorr pyrrole formation using this diketone undergoes auto-oxidation to give a fully-substituted 5-formyl pyrrole which was converted into the natural lactone B ring. Antiproliferative testing of the N-benzyl-des-D ring analogue gave an IC50 of 2.63 μM against the MDA-MB-231 breast cancer cell line. 相似文献
9.
Dennis Dittrich Heiko Tewes Christoph Wölper Dieter Bläser Stephan Schulz Joachim Roll 《Transition Metal Chemistry》2017,42(3):237-241
Reaction of [Zn4(µ4-O)(O2CCH3)6] with one equivalent of 4-tertiary-butylpyridine leads to a nearly quantitative formation of the heptanuclear cluster [Zn7O2(O2CCH3)10(tbupy)2] (1). Here, we present the crystal structure of 1 and first results of the examination of its catalytic activity in transesterification reactions and polymerization of lactide compared to the activity of [Zn4(µ4-O)(O2CCH3)6] in the presence of 4-tertiary-butylpyridine. 相似文献