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81.
82.
Budzelaar PH Moonen NN de Gelder R Smits JM Gal AW 《Chemistry (Weinheim an der Bergstrasse, Germany)》2000,6(15):2740-2747
The bulky ligands L(X)- (L(X) = (2,6-C6H3X2)NC(Me)CHC(Me)N(2,6-C6H3X2), X =Cl, Me) can be used to generate fluxional mononuclear arene complexes [L(X)Rh(eta4-arene)] (arene = benzene, toluene, m-xylene, mesitylene), which for X = Me disproportionate to fluxional dinuclear complexes [[L(Me)Rh]2(anti-mu-arene)]. For both mononuclear and dinuclear complexes, steric interactions do not stop the fluxionality but govern the preferred orientation of the methyl-substituted arenes, thus allowing indirect determination of the static NMR parameters. For the mu-arene complexes, two distinct types of fluxionality are proposed on the basis of calculations: ring rotation and metal shift. In the solid state, the toluene complex has an eta4(1,2,3,4):eta4(3,4,5,6)-bridged structure; the NMR analysis indicates that the benzene and m-xylene complexes have similar structures. The mesitylene complex, however, has an unprecedented eta3(1,2,3):eta3(3,4,5)-bridged structure, which is proposed to correspond to the transition state for arene rotation in the other cases. Steric factors are thought to be responsible for this reversal of stabilities. 相似文献
83.
E. Drs S. Baumgartner M. Bremer A. Kemmers-Voncken N. Smits W. Haasnoot J. Banks P. Reece C. Danks V. Tomkies U. Immer K. Schmitt R. Krska 《Analytica chimica acta》2004,520(1-2):223-228
The development of an indirect competitive enzyme-immunoassay for the detection of hidden hazelnut protein in complex food matrices is described. A sensitive and selective polyclonal antibody was raised by immunisation of laying hens with protein extracts from roasted hazelnuts. In contrast to traditional antibody generation in mammals, the antibody was not isolated from the blood of immunised mammals but from the egg yolk of immunised chickens. A standard calibration curve was optimised using immunoaffinity purified antibody extract and a coating antigen concentration of 10 μg ml−1. One percent skim milk powder was chosen for blocking. The assay has a minimum detection limit of 10 μg l−1, with an IC50 of 618 μg l−1 when a 50 mM phosphate buffer at pH 7.5 and 10 mM sodium chloride is used as assay buffer. The cross reactivity testing shows a high specificity for hazelnut proteins and various foods and food additives were found to be non reactive except beans, sunflower seed or poppy seed. 相似文献
84.
Summary Olefinic compounds are reacted with ozone in CCl4/CH3OH solution, yielding specific cleavage products, from which the original position of the double bond can be deduced. By reduction with dimethylsulfide the resulting methoxyhydroperoxides are converted into aldehydes and ketones, which are determined by temperature-programmed gas chromatography on silicone columns. The lower compounds (C1-C10) are analyzed as dinitrophenylhydrazones, the less volatile higher ones as such. 100% yields were obtained for monoolefins of different structures and chain lengths (up to C30).
Ozonolytische Bestimmung von Doppelbindungen in Olefinen durch Gas-Chromatographie
Zusammenfassung Die Olefine werden in CCl4/CH3OH-Lösung mit Ozon behandelt, wodurch spezifische Spaltprodukte entstehen, aus denen man die ursprüngliche Lage der Doppelbindung ableiten kann. Die entstandenen Methoxyhydroperoxide werden durch Reduktion mit Dimethylsulfid zu Aldehyden und Ketonen umgesetzt, die durch temperaturprogrammierte Gas-Chromatographie an Siliconsäulen analysiert werden. Die niedrigeren (C1-C10) Verbindungen werden als Dinitrophenylhydrazone bestimmt, die weniger flüchtigen höheren als solche. Für aliphatische Monoolefine verschiedener Struktur und Kettenlänge (bis C30) wurden 100%ige Ausbeuten erhalten.
Lecture presented at Euroanalysis I Conference, 28. 8.–1. 9. 1972 in Heidelberg, Germany. 相似文献
85.
Molecular structure of 3-(3-oxo-bicyclo[2.2.1]hept-5-en-2-yl)-oxirane-2-carboxylic acid methyl ester
René de Gelder Twan van Enckevort J. M. M. Smits Paul T. Beurskens Jie Zhu A. J. H. Klunder 《Journal of chemical crystallography》1996,26(1):81-84
The crystal and molecular structure of an epoxy ester is described. The structure has been solved by vector search methods and refined by least squares methods toR
1=0.0372 [I>2(I)]. The structure consists of two independent molecules in the asymmetric unit. These molecules are chemically the same. Crystal data: C11H12O4, triclinic, space group
,a=10.324(3),b=10.553(7),c=10.869(5)Å, =61.77(4), =88.64(4), =88.16(6)°,V=1042.7(9)Å3,Z=4. 相似文献
86.
87.
Smits Jan M. M. Bour Jan J. Vollenbroek Frans A. Beurskens Paul T. 《Journal of chemical crystallography》1983,13(5):355-363
Journal of Chemical Crystallography - The reaction of Au11[P(p-ClC6H4)3]7(SCN)3 with 1,3-bis(diphenylphosphino) propane (dppp) in methylene chloride leads to the formation of [Au11(dppp)5] (SCN)3... 相似文献
88.
Smits Jan M. M. Beurskens Paul T. Bour Jan J. Vollenbroek Frans A. 《Journal of chemical crystallography》1983,13(5):365-372
Journal of Chemical Crystallography - A redetermination of the crystal structure of the gold cluster [Au9{P(p-MeC6H4)3}8](PF6)3 has been performed. The compound crystallizes in the tetragonal space... 相似文献
89.
J. M. M. Smits Paul T. Beurskens A. J. H. Klunder M. J. F. M. Crul 《Journal of chemical crystallography》1986,16(5):665-671
The structure of the title compound, C12H16O3, was determined by X-rays.M
r
=208.26, triclinic, space groupP¯1,a=7.802(2),b=8.449(2),c=9.069(1) Å,=90.79(1)°,=105.57(1)°, =106.07(1)°,Z=2,D
x
=1.26 Mg m–3; MoK radiation (graphite crystal monochromator, =0.71069 Å),(MoK)=0.96 cm–1,T=290 K. Final conventionalR-factor=0.046,R
w
=0.067 for 3009 observed reflections and 184 variables. The structure was solved using Patterson methods andDirdif, and the resulting all cis-endo configuration of the alcohol group on C(3) and the ethoxy group on C(5) shows that the stereochemistry of the metal-mediated addition reaction involved is solely determined by steric factors. 相似文献
90.
J. M. M. Smits P. T. Beurskens R. Plate H. C. J. Ottenheijm 《Journal of chemical crystallography》1986,16(6):957-966
The structure of the title compound, C18H20N2O5, was determined by X-rays atT=290 K.M
r
=344.366, monoclinic, space groupP21/c,a=13.7850(8),b=8.8951(7),c=15.1603(11) Å, =111.410(6)°,V
c
=1730.7 Å3,Z=4,D
x
=1.322 Mgm–3. Cu K radiation (graphite crystal monochromator, =1.54178 Å),(Cu K)=7.69 cm–1. Final conventionalR-factor=0.057,R
w
=0.076 for 2160 observed reflections and 271 variables. The structure was solved usingMultan. 相似文献