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991.
Jean M. J. Tronchet Jean-Richard Neeser Etienne J. Charollais 《Helvetica chimica acta》1977,60(1):243-246
Cyclic and acyclic phosphate esters of some 1,2-O-isopropylidene-α-D -pentofuranoses When treated with monophenyl phosphorodichloridate, 1,2-O-isopropylidene-α-D -xylofuranose gave the two possible, isolable isomers of the corresponding 3,5-cylic phenylphosphate. Upon phosphorylation of the same sugar derivative using bis (2,2,2-trichloroethyl) phosphorochloridate only one isomer was formed. The same situation obtained when preparing 1,2-O-isopropylidene-α-D -ribofuranose-3,5-cyclic phenylphosphate. The synthesis of a new kind of sugar phosphate with a branched-chain unsaturated sugar moiety namely the trans-3-deoxy-3-C-cyanomethylene-1,2-O-isopropylidene-D -erytho-pentofuranose 5-bis(2,2,2-trichloroethyl) phosphate is also described. 相似文献
992.
The use of a contaminated single oil drop on a screen‐printed carbon electrode is described for the first time here. The simple methodology developed herein opens the possibility of conducting such measurements. R‐(+)‐limonene oil, some samples of which were contaminated with 4‐nitrophenol (4‐NP), was used as the oil phase, and Britton? Robinson (BR) buffer was used as the aqueous phase. An oxidation peak at approximately 0.8 V vs. Ag was obtained when the system comprised an oil/water interface. The charge transfer resistance decreased by a factor of approximately 7.1 when an interfacial system composed of two immiscible liquids was used as an electrochemical tool. 相似文献
993.
Etienne Labalme Ghislain David Pierrick Buvat Jannick Bigarre Thomas Boucheteau 《Journal of polymer science. Part A, Polymer chemistry》2012,50(7):1308-1316
This work concerns the development of hybrid organic/inorganic membranes from styrenic phosphonic polymers. The phosphonic charge, composed phosphonic polymers grafted onto silica nanoparticles, was obtained by “grafting onto” method. It consists of synthesizing first the polymer, and then the terminal functions of the latter react with silanol groups of silica. The phosphonated polymer was isolated in two steps, that is, an ATRP polymerization of 4‐chloromethylstyrene followed by Mickaelïs‐Arbusov reaction. After the grafting onto silica, membranes are prepared through formulation containing the charge and the polymer matrix PVDF‐HFP, which are dispersed in DMF. The acid form is obtained by hydrolysis in chlorydric acid. The membrane possessing a 40 wt % charge ratio (IEC = 1.08 meq g?1) was selected as reference. A proton conductivity of 65 mS cm?1 at 80 °C was measured in immersed conditions. When the membrane is no more immersed, the value decreases drastically (0.21 mS cm?1 at 120 °C and 25% RH). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
994.
Benoît Riflade Julie Oble Ludwig Chenneberg Etienne Derat Bernold Hasenknopf Emmanuel Lacôte Serge Thorimbert 《Tetrahedron》2013,69(27-28):5772-5779
The phosphovanadotungstate polyanion [P2W15V3O62]9? is a powerful support to stabilize palladacycles conjugated to the inorganic framework via an organic ligand. The insertion can be directed toward sp2 or sp3 C–H insertion upon appropriate choice of the substitution pattern on the organic ligand. DFT modeling indicates that the strong withdrawing effect of the POM transmitted through the conjugated carbonyl was responsible for this easy insertion. The palladacycles led to the formation of stilbene via a Mizoroki–Heck reaction. However it is likely that the POMs act as Pd-reservoirs for the formation of nanoparticles. 相似文献
995.
Frederic Robin Stephane Lelièvre Franc˛ois Mercier Louis Ricard Franc˛ois Mathey 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6-7):1371-1374
Recent developments in the chemisty of 1-phosphanorbornadienes are reviewed. Due to their bicyclic structure with a non-racemisable phosphorus atom at the bridgehead, they are ideally suited to enantioselective catalysis as transition metal complexes. Amongst this family, two enantiopure species play a special role, i.e., the so-called BIPNOR, a 2,2'-bis-1,1'-phosphanorbornadienyl ( 1 ), and a 2-formyl-1-phosphanorbornadiene ( 2 ). BIPNOR displays high enantioselectivities for a range of rhodium-catalyzed reactions. The carboxyaldehyde ( 2 ) is an ideal starting point for the synthesis of a series of enantiopure chelating 1-phosphanorbornadienes whose structures can be optimized for various catalytic enantioselective reactions. Examples of both approaches are given. 相似文献
996.
997.
Anne‐Laure Brocas Gabriel Cendejas Sylvain Caillol Alain Deffieux Stephane Carlotti 《Journal of polymer science. Part A, Polymer chemistry》2011,49(12):2677-2684
Poly(allyl glycidyl ether) and poly(allyl glycidyl ether‐co‐epichlorohydrin) were prepared by monomer‐activated anionic polymerization. Quantitative and controlled polymerization of allyl glycidyl ether (AGE) giving high molar mass polyether was achieved in a few hours at room temperature in toluene using tetraoctylammonium salt as initiator in presence of an excess of triisobutylaluminum ([i‐Bu3Al]/[NOct4Br] = 2?4). Following the same polymerization route, the copolymerization of AGE and epichlorohydrin yields in a living‐like manner gradient‐type copolymers with controlled molar masses. Chemical modification of the pendant allyl group into cyclic carbonate was then investigated and the corresponding polymers were used as precursors for the isocyanate‐free synthesis of polyurethane networks in presence of a diamine. Formation of crosslinked materials was followed and characterized by infrared and differential scanning calorimetry. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
998.
Ouaiss Abdelkader Sylvie Moebs‐Sanchez Yves Queneau Julien Bernard Etienne Fleury 《Journal of polymer science. Part A, Polymer chemistry》2011,49(6):1309-1318
Original carbohydrate‐based acrylamides bearing one azide group in C‐2 or C‐6 position namely, 2‐[(2‐deoxy‐2‐azido‐α‐D ‐mannopyranosyloxy)ethanamido]‐ethyl acrylamide (II) and 2‐[(6‐deoxy‐6‐azido‐α‐D ‐glucopyranosyloxy)ethanamido]‐ethyl acrylamide (III), and their azide‐free analogue, 2‐[(α‐D ‐glucopyranosyloxy)ethanamido]‐ethyl acrylamide (I), have been designed. Whereas the reversible addition fragmentation chain transfer (RAFT) process ensured the preparation of well‐defined glycopolymers from I, the polymerization of monomers II and III proved to be challenging at temperatures compatible with a thermally initiated radical process, due to the presumed concomitant 1,3‐cycloaddition reactions between the azide and the acrylamide moieties. In contrast to III, for which no polymer could be obtained under any conditions, performing the RAFT polymerization of II at 30 °C clearly favored the radical polymerization and conferred a controlled character to the process, affording well‐defined azide‐functionalized glycopolymers and block copolymers. The presence of numerous azide moieties was finally exploited to introduce carbohydrates onto the glycopolymer backbone through copper catalyzed azide‐alkyne cycloaddition. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
999.
Gérard Calleja Axel Houdayer Sylvie Etienne‐calas David Bourgogne Valérie Flaud Gilles Silly Sota Shibahara Atsushi Takahara Alex Jourdan André Hamwi Bruno Ameduri 《Journal of polymer science. Part A, Polymer chemistry》2011,49(7):1517-1527
Direct fluorination of poly(ethylene‐alt‐tetrafluoroethylene) copolymer (ETFE) was carried out on commercially available ETFE films with pure fluorine gas at ambient atmosphere. Reaction temperature was either 95 °C or 150 °C and exposure time was 20 hours. Analysis of the fluorinated samples was performed by attenuated total reflection Fourier transform Infrared, confocal micro‐Raman and 1H and 19F magic angle spinning nuclear magnetic resonance spectroscopies, scanning electron microscopy, electron diffraction and X‐Ray photoelectron spectroscopies, contact angle determination, atomic force microscopy and nanoindentation measurements, and compared to those of the virgin ETFE copolymer. Integrity of the bulk materials was verified by investigating the thermal behavior of the polymers by thermogravimetric analysis and differential scanning calorimetry. Evidence for the formation of a homogeneous layer of polytetrafluoroethylene with a thickness of several microns at the surface of the copolymers with no degradation of the materials was observed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
1000.
Yves Grohens Stephane Ulvé Karine Vallée-Réhel Jean Jacques Péron Dominique Haras 《Macromolecular Symposia》2003,203(1):271-276
Contact angle measurements (captive bubble and sessile drop techniques) were used to determine the surface energy of several acrylic based polymers at the early stage of immersion (t0) in pure and salt water or after several days (tx). The sessile drop technique using various liquid probes allows the calculation of the dispersive, acid and basic components of the surface energy. Significant differences of wettability are observed between the polymers at t0 which tend to remain after immersion along with a general increase of the surface hydrophilicity. The same trend is observed by the “in-situ” captive bubble technique. The surfaces become more hydrophilic with a final contact angle, θ, ranging from 110 to 150 ± 3° in pure water and 130 to 150 ± 4° in 0,51 M salt water. The modifications of surface energy between t0 and tx are not only dependent on water diffusion. One assumption is that the degree of swelling of the immersed surface layer along with the particular dynamics resulting from a surface gel-like structure are significant factors in the measured surface thermodynamics. 相似文献