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991.
C.C. Lee K.J. Demchuk W.J. Pannekoek R.G. Sutherland 《Journal of organometallic chemistry》1978,162(2):253-269
Ligand exchange reactions between phenanthrene or 9,10-dimethylphenanthrene with ferrocene effected in the presence of AlCl3-Al were carried out under a variety of conditions. With phenanthrene (I), hydrogenation at the C-9 and C-10 positions could take place during the reaction and the cationic products obtained were the η6-phenanthrene-η5-cyclopentadienyliron and η6-9,10-dihydro-phenanthrene-η5-cyclopentadienyliron moncations (II and III), and the η6-phenanthrene---η5-cyclopentadienyliron and η6-9,10-dihydrophenanthrene---η5-cyclopentadienyliron dications (IV and V). With 9,10-dimethylphenanthrene (VI), reactions carried out in refluxing cyclohexane gave the non-hydrogenated η6-9,10-dimethylphenanthrene-η5-cyclopentadienyliron monocation (VII) and η6-9,10-dimethylphenanthrene---η5-cyclopentadienyliron dication (VIII). When higher temperatures were used in an attempt to promote hydrogenation, decomposition predominated and no cationic product could be obtained. These finding are discussed and contrasted with previous results obtained from similar reactions using anthracene or 9,10-dimethylanthracene. 相似文献
992.
Resume Un polyélectrolyte dérivé de la poly (4 vinylpyridine) a été utilisé comme échangeur d'ions liquide pour des anions mono-et-divalents entre une phase aqueuse et l'octanol normal. Le polysavon sous forme sel de pyridinium est soluble dans l'octanol et la solution organique en contact avec une phase aqueuse contenant un mélange d'électrolytes possède des propriétés échangeuses d'ions. La sélectivité de l'échangeur vis à vis d'anions de nature différente est interprétée en fonction de la polarisabilité des anions. On a déterminé l'indice viscosimétrique des solutions organiques en fonction de la composition ionique du polymère et on a établi un parallèle entre les dimensions du polymère et l'affinité des ions pour les sites pyridinium compte-tenu de la faible constante diélectrique du milieu. Les variations de la viscosité en fonction de la composition sont interprétées à partir de la théorie de Flory transposée aux copolymères statistiques.
Summary A polymer obtained by quaternizing poly (4-vinylpyridine) with N-octadecyl bromide was used in developing liquid ion-exchange of mono- and divalent anions between water and 1-octanol phases. The polymer has a high solubility in 1-octanol and the organic polymeric solution in contact with aqueous phase containing a mixture of simple electrolytes behave similary to an anion exchange resin with selective properties. The mechanism by which selective association of anions on the polymeric pyridinium sites occurs is discussed from the data concerning the polarisability of anions. The conformational properties of the polymeric chain was determined from viscosity measurements. It is shown that the trend in chain dimensions parallels the affinity of the anions to bind on polymeric pyridinium sites in the low dielectric medium. The chain dimensions as a function of the ionic composition are discussed on the basis of a simple theoretical model in analogy with the behaviour of statistical copolymers.
Zusammenfassung Eine Lösung von Poly(-4-vinylpyridinium)salz in Octanol wurde als flüssiger Anionenaustauscher zwischen einer wässerigen Lösung und Octanol gebraucht. Diese organische Lösung in Berührung mit einer wässerigen Electrolytmischung behält die Eigenschaften der Ionenaustauscher. Die Selektivität des Austauschers für verschiedene Anionen wird durch die Polarisabilität der Ionen erklärt. Die Konformation der Polymeren wurde durch Viskositätsmessungen bestimmt und mit der verschiedenen Ionenaffinität in Vergleich gestellt. Die Dimensionsveränderungen der Polymeren während des Ionenaustausches wurden durch ein einfaches Modell erklärt, analog dem der statistischen Copolymeren.相似文献
993.
It has been established that 2-(tert-butyl)-3-hydroxy-3-(4-chlorophenyl)isoindolinone and N-(tert-Alkyl)-2-aroylbenzamides are dealkylated in concentrated sulfuric acid to give 3-hydroxy-3-arylisoindolinones. The reaction is realizable. only when there is a tert-alkyl group attached to the nitrogen atom. The reaction mechanism is discussed on the basis of data on the change with time in the electronic spectra of the investigated compounds in concentrated sulfuric acid and a comparison with the spectra of model structures.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 763–765, June, 1977. 相似文献
994.
Lifetimes of Hg(3P0) complexes were determined by simultaneous observation of Hg(3P0) optical absorption and complex emission, using a modulation technique and phase sensitive detection. The lifetimes of the mercury complexes with methanol, (1.4 ± 0.7) × 10-8 s, and water, ? 8 × 10-8 s, were found to be much shorter than reported in earlier work. For the ammonia complex, however a lifetime was measured which is in good agreement with previous determinations. Reasons for the large errors in earlier work where the methanol and water complex lifetimes were determined from complex emission data alone are discussed, and these data are reinterpreted. In the reaction rate of Hg(3P0) with methanol no detectable contribution from the termolecular process Hg(3P0) + 2CH3OH → (Hg·CH3OH)* + CH3OH could be observed. 相似文献
995.
The structures of three sesquiterpenoids, axisothiocyanate-2(4), axamide-1(5) and axamide-2(6), present in the marine sponge Axinella cannabina, have been determined on the basis of chemical and spectral evidences. 相似文献
996.
R. Arshady G. W. Kenner A. Ledwith 《Journal of polymer science. Part A, Polymer chemistry》1974,12(9):2017-2025
Details are given of the synthesis and purification of p-acetoxystyrene and its solution and suspension copolymerization with styrene. Reactivity ratios, evaluated by the Tidwell-Mortimer method, were r1 (p-acetoxystyrene) = 1.18, and r2 (styrene) = 0.88 for (bulk) solution copolymerization. Corresponding values of the reactivity ratios for suspension copolymerization were, within experimental error, indistinguishable from unity. Thus the copolymer composition is governed simply by the monomer feed composition. Use of a specially designed reactor vessel permits convenient suspension copolymerization of styrene, p-acetoxystyrene, and divinylbenzene to give crosslinked resins having comparatively narrow particle size distributions. Acetoxy groups in the crosslinked resin are cleaved by hydrazine hydrate under very mild conditions to give crosslinked polystyrenes having phenolic groups which, in turn, provide a useful alternative to the more usual chloromethylated polystyrene resins for solid-phase peptide synthesis. 相似文献
997.
C. E. Brukl 《Monatshefte für Chemie / Chemical Monthly》1972,103(3):820-830
Zusammenfassung Röntgenbeugungsfilme von Pulveraufnahmen wärmebehandelter Proben wurden zur Untersuchung der Phasengleichgewichte der pseudo-ternären Subcarbidsysteme Ta2C–Mo2C(W2C)–V2C(Nb2C) bei 1650° und 2000°C herangezogen. Es werden in jedem System die Zusammensetzungs-bereiche festgestellt, in denen die bekannte Disproportionierungsreaktion zu erwarten ist. Es ist dies ein erster Schritt, um zu ermöglichen, diese Legierungen zur Herstellung von Schneide-werkzeugen heranzuziehen. In allen Systemen bilden die Subcarbidphasen ausgedehnte Einphasenbereiche. In den Nb2C enthaltenden Systemen gibt es Legierungen mit engen Zusammensetzungsbereichen, die möglicherweise als Legierungen für die Erzeugung von Schneidewerkzeugen herangezogen werden können.
Mit 4 Abbildungen
Herrn Prof.H. Nowotny gewidmet. 相似文献
The effect of vanadium and niobium on the subcarbide solid solution in the tantalum-tungsten-carbon and tantalum-molybdenum-carbon systems
The phase equilibria of the pseudo-ternary subcarbide systems Ta2C–Mo2C(W2C)–V2C(Nb2C) at 1650 and 2000°C have been investigated using X-ray powder diffraction films of heat treated samples. The compositional regions in each system where the known disproportionation reaction is expected to occur have been defined as an initial step towards the utilization of these alloys for cutting tools. The subcarbide phases form extended single phase regions in all systems. Alloys from small compositional regions in those systems containing Nb2C are possible candidates for preliminary cutting tool alloy evaluation.
Mit 4 Abbildungen
Herrn Prof.H. Nowotny gewidmet. 相似文献
998.
M. A. Haimova M. D. Palamareva C. I. Novkova B. J. Kurtev C. A. Petrova T. I. Arnaudov 《Monatshefte für Chemie / Chemical Monthly》1970,101(3):855-865
Zusammenfassung Durch Umsetzung von Hydramiden mit am aromatischen Ring m,p-dialkoxysubstituierten Arylessigsäureestern in Gegenwart von wasserfr. AlCl3 entstehen Gemische aus Estern der (±)-erythro- und (±)-threo-3-Amino-2,3-diarylpropansäuren. Bei der Umsetzung von Piperonalhydramid mit dem Methylester der Homoveratrumsäure konnte lediglich daserythro-Diastereomere isoliert werden.Die diastereomeren Ester wurden zu den jeweiligen (±)-erythro- und (±)-threo-3-Amino-2,3-diaryl-1-propanolen reduziert, die als N,O-Dibenzoylderivate charakterisiert wurden. Ihre relativen Konfigurationen und die der zugehörigen Ester wurden auf Grund der IR-Spektren der diastereomeren Aminopropanole bestimmt. Die NMR-Spektren eines Diastereomerenpaares von Aminopropanolen bestätigen die ihnen chemisch zugeordneten Konfigurationen und ermöglichen den Nachweis auch ihrer bevorzugten Konformationen.
Synthesis and configuration of methyl esters of the diastereomeric (±)-3-amino-2,3-diarylpropanoic acids, the (±)-3-amino-2,3-diaryl-1-propanols and their derivatives
Reaction of hydramides with m,p-dialkoxysubstituted arylacetates in the presence of anhydrous AlCl3 generally leads to mixtures of the esters of the (±)-erythro- and (±)-threo-3-amino-2,3-diarylpropanoic acids. However, in the reaction of piperonal hydramide with methyl homoveratrate, only the correspondingerythro-diastereomer was obtained.Reduction of the diastereomeric esters gives the corresponding (±)-erythro- and (±)-threo-3-amino-2,3-diaryl-1-propanols, which can be characterized as N,O-dibenzoyl derivatives. Relative configurations of both alcohols and esters were determined by means of their IR spectra. Configurations were confirmed for one pair of diastereomeric amino alcohols by means of NMR spectra and preferred conformations deduced.相似文献
999.
R. É. Valter É. A. Baumanis L. K. Stradynya É. É. Liepin'sh 《Chemistry of Heterocyclic Compounds》1981,17(4):375-378
The structures of 1-cyanoacetyl-2-alkylhydrazines and their ring isomers, viz., 1-alkyl-5-amino-3-pyrazolones, to which they are readily cyclized, were investigated by IR, UV, and PMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 516–519, April, 1981. 相似文献
1000.
13C and 31P chemical shift data for eight 2-methoxy-1,3,2-dioxaphosphorinanes are reported. Examination of pairs of geometrical isomers, which differ only in the orientation of the OMe substituent on PIII, have shown that both the 31P and the 13C signals of C4,6 atoms appear 3–4 ppm at higher field when the OMe is axial compared with the equatorial isomer. This observation can be associated with the 1–3 syn diaxial interaction between the phosphorus axial substituent and the axial hydrogens on C4,6 and should thus constitute, in the future, a supplementary tool for the structural analysis of this kind of compound. Important long range δ effects were observed both on 13C and especially on 31P chemical shifts. It is suggested that the high field δe effects could reflect a direct stereoelectronic interaction between the P atom and the cyclic C-5 atom. This interpretation is supported by a study of the 31P…13C coupling constants and their stereochemical dependence. 相似文献