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141.
Toward the Rational Design of Galactosylated Glycoclusters That Target Pseudomonas aeruginosa Lectin A (LecA): Influence of Linker Arms That Lead to Low‐Nanomolar Multivalent Ligands 下载免费PDF全文
Dr. Shuai Wang Lucie Dupin Mathieu Noël Cindy J. Carroux Dr. Louis Renaud Dr. Thomas Géhin Albert Meyer Dr. Eliane Souteyrand Dr. Jean‐Jacques Vasseur Dr. Gérard Vergoten Dr. Yann Chevolot Dr. François Morvan Dr. Sébastien Vidal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11785-11794
Anti‐infectious strategies against pathogen infections can be achieved through antiadhesive strategies by using multivalent ligands of bacterial virulence factors. LecA and LecB are lectins of Pseudomonas aeruginosa implicated in biofilm formation. A series of 27 LecA‐targeting glycoclusters have been synthesized. Nine aromatic galactose aglycons were investigated with three different linker arms that connect the central mannopyranoside core. A low‐nanomolar (Kd=19 nm , microarray) ligand with a tyrosine‐based linker arm could be identified in a structure–activity relationship study. Molecular modeling of the glycoclusters bound to the lectin tetramer was also used to rationalize the binding properties observed. 相似文献
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4'-Substituted nucleoside analogues have been synthesized using palladium-catalyzed asymmetric allylic amination conditions. A kinetic discrimination between the diastereomeric lactol acetates (3) produced the desired aminated products (6a-d) and recovered acetate (alpha-3) in high yields and <97:3 diastereoselectivity. Epimerization of the recovered lactol acetate (alpha-3) produced a 60:40 alpha/beta mixture of (3), which could be resubjected, in principle, to the palladium-catalyzed asymmetric allylic amination conditions. 相似文献
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Himo F Demko ZP Noodleman L Sharpless KB 《Journal of the American Chemical Society》2002,124(41):12210-12216
It is well-known that azide salts can engage nitriles at elevated temperatures to yield tetrazoles; however, there is continued debate as to the mechanism of the reaction. Density functional theory calculations with the hybrid functional B3LYP have been performed to study different mechanisms of tetrazole formation, including concerted cycloaddition and stepwise addition of neutral or anionic azide species. The calculations presented here suggest a previously unsuspected nitrile activation step en route to an imidoyl azide, which then cyclizes to give the tetrazole. The activation barriers are found to correlate strongly with the electron-withdrawing potential of the substituent on the nitrile. 相似文献
146.
Scrambling of the carbon atoms in benz[a]anthracene between positions 5 and 6 has been shown to occur at high temperatures; a mechanism involving thermal generation of a carbene is proposed. 相似文献
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Bruno Albrecht Michael Allan Edwin Haselbach Louis Neuhaus Pierre-Alain Carrupt 《Helvetica chimica acta》1984,67(1):220-223
Vinylamine 1 was prepared by thermolysis of cyclobutylamine and its photoelectron spectrum was measured. I = 8.20 eV and I = 8.65 eV were found, the dominant vibrational progression (? = 725 cm?1) indicating that in the course of 1(X)→1 +( X? ) flattening around the N-atom occurs. The Franck-Condon profile of this band, however, suggests that a skeletal mode of ? ≈ 1400 cm?1 (observed also in the iso-π-electronic systems vinyl-alcohol-cation and allyl radical) may also be excited. Comparison with the data for the isomer acetaldehyde-imine 2 and its cation s + shows that the isomer couple 1/2 constitutes a further notable example for a relative thermochemical stability inversion on going from the neutrals to the cations. 相似文献
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Arlette Clayer Louis Agneray Gérard Vandenbussche et Pierre Petel 《Fresenius' Journal of Analytical Chemistry》1968,236(1):240-249
Résumé Le procédé de séparation des isotopes de l'hydrogène par chromatographie en lit mobile présenté est un procédé continu.Le principe en est le suivant: dans une colonne verticale, un lit mobile de silicagel descend par gravité. Le mélange à séparer (protium/deutérium) est introduit au milieu de cette colonne. La séparation du mélange en ses deux constituants s'effectue par échange à contre-courant entre la phase gazeuse et la phase adsorbée. Le protium, moins adsorbé, est soutiré en tête de colonne, le deutérium est soutiré en pied. Le reflux en bas de colonne est obtenu de 2 façons différentes qui dépendent du type de désorption employé: désorption du silicagel par élévation de températuré et élution du deuté rium, par de l'hélium désorption du silicagel par élévation de température et déplacement du deutérium, par de l'azote.Dans le ler cas, les gaz produits sont dilués dans l'hélium, dans le 2ème cas ils sortent non dilués. Le silicagel est remonté en tête de colonne par un transport pneumatique. L'expérimentation présentée à été faite avec gaz de déplacement azote.
Summary The preparation-process of hydrogen isotopes by chromatography in a moving bed in a continuous process is described.The principle is as follows: In a vertical column silicagel flows downward, by gravity, in a moving bed. The gaseous mixture to be separated (protium/deuterium) is introduced into the central portion of this column. Separation of the mixture into its two constituents is achieved by a counter-current exchange between the gaseous phase and the adsorbed phase. Protium less adsorbed is withdrawn at the top, deuterium is withdrawn at the bottom. The reflux is produced, at the bottom of the column, by two differents means, depending on the type of desorption used: Silicagel-desorption by rise of temperature and deuterium-elution by helium or displacing of deuterium by nitrogen.The gases produced are mixed with helium (1st case), or not (2nd case). Silicagel is carried again onto the top of the column by pneumatic transport. The experiments presented were carried out by means of nitrogen as displacing gas.相似文献