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41.
G. Miksch E. Liebermann Friedrich Kohler 《Monatshefte für Chemie / Chemical Monthly》1969,100(5):1574-1582
Zusammenfassung Totaldampfdrucke des Systems 1,2-Dichloräthan + Cyclohexan wurden bei 13°, 20° und 32° C über den gesamten Konzentrationsbereich gemessen. Für Cyclohexan-reiche Mischungen des Systems wurde ferner die Schmelzkurve bestimmt. Aus diesen Meßgrößen wurde die zusätzliche freie Mischungsenthalpie G
E des Systems für verschiedene Temperaturen berechnet. Bei 20°C beträgt G
E für die äquimolare Mischung 773 J/mol. Ein Vergleich mit Literaturangaben über die Mischungswärme (H=1611 J/mol für äquimolare Mischung bei 20°C) ergibt, daß die zusätzliche Mischungsentropie S
E des Systems stark positiv ist. Eine Interpretation der Ergebnisse wird in einer anderen Arbeit gegeben, wo auch Ergebnisse an anderen Dihalogenäthan + Kohlenwassersoff-Systemen berücksichtigt werden.
Mit 5 Abbildungen 相似文献
Free enthalpy of mixing for the system 1,2-dichloroethne-cyclohexane
Total vapour pressures of the system 1,2-dichloroethane + cyclohexane were measured at 13°, 20° and 32°C over the total concentration interval. For mixtures rich in cyclohexane the
Mit 5 Abbildungen 相似文献
42.
Alkylation of 1-dimethylamino-1-cyanomethanephosphonic acid diethyl ester (8), easily obtainable from diethyl phosphite and the 0,N-acetal 9, yields 1-alkyl derivatives 14. Elimination of HCN converts 14 into 1-phosphonoenamines 6. Carbonyl compounds react with 8 to give 1-cyanoenamines 15 which may be hydrolyzed to from the homologous carboxylic acid. Alternatively, deprotonation of 15 yields the homoenolate anions 17 which can be alkylated or hydroxyalkylated, permitting chain extension of carbonyl compounds through introduction of an α-carboxyl and a β-alkyl group. Acid catalyzed hydrolysis of 8 results in cleavage of the PC bond, leading to the corresponding α-dimethylamino alkanoic acids. A phosphonic acid 11 can be obtained from 8 by application of the silylester method. An unambigous assignment of E/Z-isomers of the cyanoenamines 15 has been derived from 13C-NMR spectroscopy. 相似文献
43.
Christian C. Van de Sande Syed Zahoor Ahmad Friedrich Borchers Karsten Levsen 《Journal of mass spectrometry : JMS》1978,13(11):666-670
Gaseous protonated aziridine ions are produced at the threshold from β-phenoxyethylamine molecular ions. The evidence for this is collisional activation spectra, using various precursors (including labelled analogues) under electron impact and field ionization conditions. Partial conversion to the acyclic \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} {\rm CH = }\mathop {\rm N}\limits^ + {\rm H}_{\rm 2} $\end{document} isomer occurs at higher electron energies and is rationalized by means of a potential energy surface constructed from energetic data. 相似文献
44.
Laser desorption—Fourier transform mass spectrometry was utilized for the determination and quantification of mixtures of ionic surfactants, both neat and from textiles. Sodium dodecyl sulfate and the perdeuterated standard were desorbed from cotton cloth and quantified over a standard: analyte ratio range of 50. A neat C10-C14 sodium alkyl benzenesulfonate homolog mixture was also assayed, and selective analyte precipitation on the copper probe from which desorption occurs was found to be a significant factor in causing component discrimination. 相似文献
45.
Friedrich Boberg Maria Ruhr Karl-Heinz Garburg Alfons Garming 《Journal of heterocyclic chemistry》1986,23(3):759-766
Dihydro-1,2-oxazines 8 and 12-oxazines 12 are formed by the reaction of the nitronic acids of the adducts of α-nitroolefins and β-dicarbonyl compounds ( 6 ) by two ways: A ) The nitronic acids 6 are heated in a boiling solution of urea in ethanol or methanol. B ) The nitronic acids 6 are reduced with an aqueous solution of ammoniachloride and sodium sulfide. 1H-nmr and 13C-nmr investigations prove the constitutions. The mechanism is discussed. 相似文献
46.
Doz. Dr. Friedrich Höfler Ernst Brandstätter 《Monatshefte für Chemie / Chemical Monthly》1975,106(4):893-904
The reactions of Ge2(C6H5)6 with HCl and HBr lead in nearly quantitative yields to the 1,1,2,2-tetrahalo derivatives Cl2(C6H5)GeGe(C6H5)Cl2 (I) and Br2(C6H5)GeGe(C6H5)Br2 (II), resp. The Si?Ge bond of (C6H5)3SiGe(C6H5)3 is cleaved under the conditions of hydrohalogenation. The vibrational spectra of Ge2Br6, Ge2(C6H5)6, I, and II are reported. The influence of vibrational coupling on ν GeGe in these compounds is discussed in detail, including vibrational calculations. 相似文献
47.
D. H. E. Gross R. C. Nayak L. Satpathy 《Zeitschrift für Physik A Hadrons and Nuclei》1981,299(1):63-72
The friction model for heavy ion induced fusion and deep inelastic nuclear reaction is extended to include deformation. Spheroidal deformation and relative motion of the mass centres of the two interacting nuclei are treated as dynamical variables. The radial frictional force has been assumed to be proportional to the rate of change of the separation between the two surfaces instead of the two centres of mass. The friction coefficients remain unaltered. The potential as a function of deformation and separation distance are generated by a single folding procedure. The model is applied to40Ar+232Th at 379 MeV (Lab) and136Xe+209Bi at 1,130 MeV (Lab). In case of the former, the energy loss, which has not been properly accounted for before, is now satisfactorily explained and in the case of the latter the model predicts the absence of fusion in agreement with experiment. 相似文献
48.
Preparation and Crystal Structure of Cadmium Azide Cd(N3)2 Solvent free, binary cadmium azide was synthesized by the reaction of cadmium carbonate and a 24 weight% solution of HN3 in water. Cadmium azide is a colorless, crystalline powder which is highly sensitive to percussion and heat. Caution, the manipulation of Cd(N3)2 is very dangerous! The crystal structure was solved by single‐crystal methods and the phase purity was verified by a Rietveld refinement (Cd(N3)2, Pbca, no. 61; a = 7.820(2), b = 6.440(2), c = 16.073(3) Å; Z = 8, 1174 independent reflections, 64 parameters, R1 = 0.022). Cadmium azide crystallizes in a new structure type. In the crystal there are edge‐sharing Cd2(N3)10 double octahedrons which are further connected to other units by azide bridges. Vibrational spectroscopic investigations (Raman an IR) are discussed with respect to the crystal structure data. 相似文献
49.
The mechanism of propene elimination from metastable methyleneimmonium ions is discussed. The first field-free region fragmentations of complete sets of isotopically labelled methyleneimmonium ions (H2C = $ \mathop {\rm N}\limits^{\rm +} $+R1R2: R1 = R2 = n-C3H7; R1 = R2 = i-C3H7; R1 = n -C3H7; R2 = C2H5; R1 = n-C3H7; R2 = CH3; R1 = n-C3H7; R2 = H) were used to support the mechanism presented. The relative amounts of H/D transferred are quantitatively correlated to two distinct mathematical concepts which allow information to be deduced about influences on reaction pathways that cannot be measured directly. Propene loss from the ions examined proceeds via ion-neutral complex intermediates. For the di-n-propyl species rate-determining and H/D distribution-determining steps are clearly distinct Whereas the former corresponds to a 1,2-hydride shift in a 1-propyl cation coordinated to an imine moiety, the latter is equivalent to a proton transfer to the imine occurring from the 2-propyl cation generated by the previous step. For the diisopropyl-substituted ions which directly form the 2-propyl cation-containing complex, the rate-determining hydride shift vanishes. The 2-propyl cation-containing complex can decompose directly or via an intermediate proton-bridged complex. Competition of these routes is not excluded by the experimental results. Assuming a 2:1:3 distribution, a preference for the α- and β-methylene of the initial n-propyl chain as the source of the hydrogen transferred is detected for n-propylimmonium ions containing a second alkyl chain R2. This preference shows a clear dependence on the steric influence of R2. During the transfer step isotopic substitution is found to affect the H/D distribution strongly. For the alternative route of McLafferty rearrangement leading to C2H4 loss, specific γ-H transfer is observed. 相似文献
50.
Equilibrium Measurements by the Transport Method. Determination of the Enthalpie of Formation ΔH°(NbOCl2,f) by Chemical Transport in the Diffusion Tube By means of chemical transport in an ampoule with a well defined diffusion path the equilibrium NbOCl2,s + NbCl5,g ? NbOCl3,g + NbCl4,g has been investigated. Introducing a reaction entropy ΔS = 45 cl one gets ΔH = 38(±2) kcal/formula weight and ΔH0(NbOCl2,s)= ?187,6 kcal/mol. 相似文献