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51.
52.
Damien Montarnal Philippe Cordier Corinne Soulié‐Ziakovic François Tournilhac Ludwik Leibler 《Journal of polymer science. Part A, Polymer chemistry》2008,46(24):7925-7936
We describe the synthesis of supramolecular self‐healing elastomers from vegetable oil fatty acid derivatives, diethylene triamine, and urea. Our strategy to obtain materials that are self‐healing but do not flow relies on the use of a wide molecular distribution of randomly branched oligomers equipped with self‐complementary and complementary hydrogen bonding groups. We prepared such oligomers with a two steps procedure. In the first step, diethylene triamine was condensed with dimer acids. In the second step, the oligomers obtained were allowed to react with urea. The molecules were characterized by NMR and IR spectroscopies and Monte‐Carlo simulations were used to analyze the molecular size distribution. The sensitivity to small variations of the experimental conditions has been examined and the robustness of the synthetic procedure optimized. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7925–7936, 2008 相似文献
53.
Damien Habrant 《Tetrahedron》2009,65(38):7927-555
A stereoselective synthesis of the C13-C25 of Calyculin C is described. Key steps involve the coupling of a terminal acetylene with a thiol ester and subsequent spirocyclisation using a double intramolecular hetero-Michael addition. 相似文献
54.
Dieter Muri Clémence Corminboeuf Erick M. Carreira Damien Jeannerat 《Magnetic resonance in chemistry : MRC》2009,47(11):909-916
We discuss and demonstrate the potential of HSQC‐TOCSY and HSQC‐NOESY experiments to offer solutions for overlap problems in COSY and NOESY spectra, leading to improved signals that can be unambiguously assigned to individual carbons. Direct comparison of experimental 1H and 13C chemical shielding with density functional theory (DFT)‐calculated values are uninformative; in contrast, the relative differences in experimental shielding between pairs of molecules correlates well with the relative differences in DFT‐GIAO shielding for the computed lowest energy conformers. A detailed application of both experimental and theoretical techniques is illustrated for slowly exchanging conformers of an erythronolide A derivative, which demonstrates that structure determination can strongly benefit from the interplay between experiment and theory. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
55.
Rünzi T Guironnet D Göttker-Schnetmann I Mecking S 《Journal of the American Chemical Society》2010,132(46):16623-16630
Polymerization of ethylene by complexes [{(P^O)PdMe(L)}] (P^O = κ(2)-(P,O)-2-(2-MeOC(6)H(4))(2)PC(6)H(4)SO(3))) affords homopolyethylene free of any methyl methacrylate (MMA)-derived units, even in the presence of substantial concentrations of MMA. In stoichiometric studies, reactive {(P^O)Pd(Me)L} fragments generated by halide abstraction from [({(P^O)Pd(Me)Cl}μ-Na)(2)] insert MMA in a 1,2- as well as 2,1-mode. The 1,2-insertion product forms a stable five-membered chelate by coordination of the carbonyl group. Thermodynamic parameters for MMA insertion are ΔH(++) = 69.0(3.1) kJ mol(-1) and ΔS(++) = -103(10) J mol(-1) K(-1) (total average for 1,2- and 2,1-insertion), in comparison to ΔH(++) = 48.5(3.0) kJ mol(-1) and ΔS(++) = -138(7) J mol(-1) K(-1) for methyl acrylate (MA) insertion. These data agree with an observed at least 10(2)-fold preference for MA incorporation vs MMA incorporation (not detected) under polymerization conditions. Copolymerization of ethylene with a bifunctional acrylate-methacrylate monomer yields linear polyethylenes with intact methacrylate substituents. Post-polymerization modification of the latter was exemplified by free-radical thiol addition and by cross-metathesis. 相似文献
56.
Nechab M Campolo D Maury J Perfetti P Vanthuyne N Siri D Bertrand MP 《Journal of the American Chemical Society》2010,132(42):14742-14744
The cascade rearrangement of chiral enediynes 1c-e, involving successively 1,3-proton shift, Saito-Myers cyclization, 1,5-hydrogen atom transfer, and intramolecular coupling of the resulting biradical, proceeded at 80 °C to form tri- and tetracyclic heterocycles possessing a quaternary stereogenic center with a very high level of memory of chirality. 相似文献
57.
This work describes the conditions of use of bare gold electrode to detect electrochemically the presence of peroxynitrite ONOO? in phosphate buffer solution at pH 7.1. As ONOO? is extremely unstable in neutral solution, current–potential curve was reconstructed between ?0.5 and 0.7 V vs SCE by amperometry experiments at rotating disk electrode at different potentials. Comparison of this reconstructed curve with voltammograms of the common interfering species (dopamine, hydrogen peroxide, nitrite, ascorbic acid and glutamate) shows that the presence of ONOO? can be selectively determined at ?0.1 V vs SCE. This detection occurs through the electrochemical reduction of peroxynitrous acid ONOOH, the conjugated acid of ONOO?. Detection of ONOO? produced in situ by the reaction of nitric oxide with superoxide was also achieved. 相似文献
58.
59.
Cyrielle Roquelet Jean‐Sébastien Lauret Dr. Valérie Alain‐Rizzo Dr. Christophe Voisin Dr. Romain Fleurier Dr. Morgan Delarue Damien Garrot Dr. Annick Loiseau Prof. Philippe Roussignol Prof. Jacques A. Delaire Prof. Emmanuelle Deleporte Prof. 《Chemphyschem》2010,11(8):1667-1672
We report on a new, original and efficient method for π‐stacking functionalization of single‐wall carbon nanotubes. This method is applied to the synthesis of a high‐yield light‐harvesting system combining single‐wall carbon nanotubes and porphyrin molecules. We developed a micelle‐swelling technique that leads to controlled and stable complexes presenting an efficient energy transfer. We demonstrate the key role of the organic solvent in the functionalization mechanism. By swelling the micelles, the solvent helps the non‐water‐soluble porphyrins to reach the micelle core and allows a strong enhancement of the interaction between porphyrins and nanotubes. This technique opens new avenues for the functionalization of carbon nanostructures. 相似文献
60.
Damien Montange Michel Bérard Martin Demarchi Patrice Muret Sarah Piédoux Jean Pierre Kantelip Bernard Royer 《Journal of mass spectrometry : JMS》2010,45(6):670-677
The anticancer drug capecitabine and its metabolites [including the active metabolite 5‐fluorouracil (5‐FU)] display high pharmacokinetic inter‐patient variability. Such variability, which may lead to treatment failure or toxicity, could need drug concentration measurement to individualize dosing regimen. However, usual assay methods are often long and fastidious. A simultaneous and cost‐effective method was thus developed for the determination of the concentrations of these compounds in human plasma. Compounds were extracted via a classic liquid–liquid extraction. Chromatographic analysis was performed on a C18 reverse phase column with detection by atmosphere pressure chemical ionization LC‐MS/MS. Our method allows a good chromatographic separation of the compounds and was fully validated following Food and Drug Administration (FDA) recommendations (good selectivity, no carry‐over, linearity of the calibration curves without weighting, deviations from nominal concentrations of standard samples lower than 15%, intra‐ and inter‐assay precision and accuracy lower than 15%). Recovery and stability were also acceptable following the FDA guidelines. A matrix effect impairing the determination of 5‐FU was avoided by using a stable isotopic derivative of 5‐FU as internal standard. Interestingly, this method allows detection of TetraHydroUridine, an inhibitor of ex vivo degradation of metabolites, which is essential for the stability, the adequate conditioning of blood samples and for good laboratory practice, essential in routine determination. This method seems usable to routinely determine concentrations of capecitabine and its metabolites in blood and may be helpful in further studies aiming at performing therapeutic drug monitoring. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献