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81.
Dr. Natalya V. Izarova Dr. Beatrix Santiago‐Schübel Dr. Sabine Willbold Dr. Volkmar Heß Prof. Dr. Paul Kögerler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(45):16052-16056
Two polyanions [SeI V2PdII4WVI14O56H]11? and [SeI V4PdII4WVI28O108H12]12? are the first hybrid polyoxometalates in which classical (Group 5/6 metal based) and non‐classical (late transition‐metal based) polyoxometalate units are joined. Requiring no supporting groups, this co‐condensation of polyoxotungstate and isopolyoxopalladate constituents also provides a logical link between POM‐PdII coordination complexes and the young subclass of polyoxopalladates. Solid‐state, solution, and gas‐phase studies suggest interesting specific reactivities for these hybrids and point to several potential derivatives and functionalization strategies. 相似文献
82.
Martin F. Schneider Carola Gantner Werner Obrecht Oskar Nuyken 《Journal of polymer science. Part A, Polymer chemistry》2011,49(4):879-885
The ring‐opening metathesis polymerization (ROMP) of cis‐cyanocyclooct‐4‐ene initiated by ruthenium‐based catalysts of the first, second, and third generation was studied. For the polymerization with the second generation Grubbs catalyst [RuCl2(?CHPh)(H2IMes)(PCy3)] (H2IMes = N,N′‐bis(mesityl)‐4,5‐dihydroimidazol‐2‐ylidene), the critical monomer concentration at which polymerization occurs was determined, and variation of monomer to catalyst ratios was performed. For this catalyst, ROMP of cis‐cyanocyclooct‐4‐ene did not show the features of a living polymerization as Mn did not linearly increase with increasing monomer conversion. As a consequence of slow initiation rates and intramolecular polymer degradation, molar masses passed through a maximum during the course of the polymerization. With third generation ruthenium catalysts (which contain 3‐bromo or 2‐methylpyridine ligands), polymerization proceeded rapidly, and degradation reactions could not be observed. Contrary to ruthenium‐based catalysts of the second and third generation, a catalyst of the first generation was not able to polymerize cis‐cyanocyclooct‐4‐ene. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
83.
Christoph Dorn Selina Schießer Beatrix Wulkersdorfer Florian Hitzenbichler Martin G. Kees Markus Zeitlinger 《Biomedical chromatography : BMC》2020,34(6):e4820
Pharmacokinetic/pharmacodynamic indices of anti-infective drugs should be referenced to free drug concentrations. In the present study, clindamycin, flucloxacillin and tedizolid have been determined in human plasma by HPLC–UV. The drugs were separated isocratically within 3–6 min on a C18 column using mixtures of phosphate buffer–acetonitrile of pH 7.1–7.2. Sample treatment for the determination of total drug concentrations in plasma included extraction/back-extraction (clindamycin) or protein precipitation (flucloxacillin, tedizolid). The free drug concentrations were determined after ultrafiltration. An ultrafiltration device with a membrane consisting of regenerated cellulose proved to be suitable for all drugs. Maintaining a physiological pH was crucial for clindamycin, whereas maintaining body temperature was essential for tedizolid. The methods were applied to the analysis of total and free drug concentrations in clinical samples and were sufficiently sensitive for pharmacokinetic studies and therapeutic drug monitoring. 相似文献
84.
C.?Marco?Polo?Castillo Villalba Fabrizio?ColomboEmail author Jonathan?Gantner J.?Oscar?González-Cervantes 《Complex Analysis and Operator Theory》2015,9(2):479-517
In this paper we begin the study of some important Banach spaces of slice hyperholomorphic functions, namely the Bloch, Besov and weighted Bergman spaces, and we also consider the Dirichlet space, which is a Hilbert space. The importance of these spaces is well known, and thus their study in the framework of slice hyperholomorphic functions is relevant, especially in view of the fact that this class of functions has recently found several applications in operator theory and in Schur analysis. We also discuss the property of invariance of these function spaces with respect to Möbius maps by using a suitable notion of composition. 相似文献
85.
86.
R. Zaghloul E. Gantner M. Mostafa H. J. Ache 《Journal of Radioanalytical and Nuclear Chemistry》1987,109(2):283-294
A physical approach is described for instrumental multielement activation analysis with whole neutron spectrum (without Cd-cover) using the monostandard (single comparator) method. To test the capabiliteries of this method, 15 samples representing different Egyptian granite rocks were analyzed. As many as 21 trace elements beside Fe, K and Na were determined. Calculation of the experimental data has been done using the Gamma-Monostandard Analysis program with the Commodore Computer available at the Institute of Radiochemistry at Garching near München. The accuracy of the method for nondestructive multielement analysis agrees within 3% with the relative method using multielement standards. 相似文献
87.
Josef Pernerstorfer Michael Brands Hartmut Schirok Beatrix Stelte-Ludwig Elisabeth Woltering 《Tetrahedron》2004,60(39):8627-8632
An approach to combine the advantages of random and of focused combinatorial libraries in pharmaceutical research is described with the example of a solid phase synthesis of 2,5-disubstituted thiadiazole ethers. Key steps of synthesis are the introduction of the heterocycle by selective, sequential nucleophilic double substitution of 2,5-bis(methylsulfonyl)-1,3,4-thiadiazole and the oxidation of the benzylsulfanyl-1,3,4-thiadiazole to the corresponding sulfone using MCPBA on solid phase. 相似文献
88.
89.
Jens P. Eußner Beatrix E. K. Barth Eliza Leusmann Zhiliang You Niklas Rinn Prof. Dr. Stefanie Dehnen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(41):13792-13802
The synthesis of new functionalized organotin‐chalcogenide complexes was achieved by systematic optimization of the reaction conditions. The structures of compounds [(R1, 2Sn)3S4Cl] ( 1 , 2 ), [((R2Sn)2SnS4)2(μ‐S)2] ( 3 ), [(R1, 2Sn)3Se4][SnCl3] ( 4, 5 ), and [Li(thf)n][(R3Sn)(HR3Sn)2Se4Cl] ( 6 ), in which R1=CMe2CH2C(O)Me, R2=CMe2CH2C(NNH2)Me, and R3=CH2CH2COO, are based on defect heterocubane scaffolds, as shown by X‐ray diffraction, 119Sn NMR spectroscopy, and ESI mass spectrometry analyses. Compounds 4 , 5 , and 6 constitute the first examples of defect heterocubane‐type metal‐chalcogenide complexes that are comprised of selenide ligands. Comprehensive DFT calculations prompted us to search for the formal intermediates [(R1SnCl2)2(μ‐S)] ( 7 ) and [(R1SnCl)2(μ‐S)2] ( 8 ), which were isolated and helped to understand the stepwise formation of compounds 1 – 6 . 相似文献
90.
Preinerstorfer B Lubda D Mucha A Kafarski P Lindner W Lämmerhofer M 《Electrophoresis》2006,27(21):4312-4320
A nonaqueous CEC method for the simultaneous separation of the four stereoisomers of the N-benzyloxycarbonyl phosphinic pseudodipeptide methyl ester benzyloxycarbonyl-homophenylalanine Z-hPhepsi(PO2HCH2)Phe-OCH3 as well as of the corresponding N-2,4-dinitrophenyl (DNP)-derivative with free C-terminal carboxylic group DNP-hPhepsi(PO2HCH2)Phe-OH was developed. For this purpose, a monolithic silica capillary column modified with a cinchona alkaloid-derived anion-exchange-type chiral selector, namely O-9-(tert-butylcarbamoyl)quinidine (tBuCQD) was prepared. The mobile phase composition (ACN/methanol ratio, counterion type) was thoroughly optimized to end up with baseline resolution of all four stereoisomers with critical resolution of as high as about 2. The CEC method proved to be superior over the corresponding HPLC separations primarily due to significantly enhanced plate numbers (between 200,000 and 600,000 m(-1) in CEC). Diastereoselectivity contributions arising from electrophoretic mobility differences of the diastereomers facilitated the separation of the later eluted diastereomeric peak pair (peaks III and IV), but had a negative influence on the selectivity of the earlier eluted diastereomeric peak pair (peaks I and II). The stereoselective CEC assay allowed the assessment of the stereoisomeric purity of the individual isomers which were obtained by preparative HPLC on a CHIRALPAK QD-AX column that is based on the same tBuCQD selector. The present study demonstrates that there exist problems which are hard to solve by HPLC, yet can be conveniently solved by CEC. Moreover, it was intended to prove by this practical application that CEC with monolithic columns is robust enough to be used for solving real-life problems. 相似文献