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71.
Jeanne Wald Kerr 《代数通讯》2013,41(8):1779-1787
72.
73.
74.
Aurlie Mac Nora Hellou Joanna Hammoud Clothilde Martin Etienne S. Gauthier Ludovic Favereau Thierry Roisnel Elsa Caytan Ghassan Nasser Nicolas Vanthuyne J. A. Gareth Williams Fabienne Berre Bertrand Carboni Jeanne Crassous 《Helvetica chimica acta》2019,102(4)
A new enantiopure cyclometallated iridium complex bearing a [4]helicenic ‐coordinating and two ‐coordinating dfppy (2‐(2,4‐difluorophenyl)‐pyridyl) ligands was prepared. This complex displayed long‐lived phosphorescence both in solution and in the solid state. Its chiroptical properties, namely electronic circular dichroism and circularly polarized luminescence, were also examined. Comparison with former chiral complexes enabled assignment of the ΔIr‐(?) and ΛIr‐(+) absolute configurations. 相似文献
75.
Dr. Lenka Pallova Dr. Etienne S. Gauthier Dr. Laura Abella Marion Jean Dr. Nicolas Vanthuyne Dr. Vincent Dorcet Dr. Laure Vendier Prof. Jochen Autschbach Dr. Jeanne Crassous Dr. Stéphanie Bastin Dr. Vincent César 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(28):7722-7730
The straightforward, multigram-scale synthesis of the partially saturated H6-fluoreno[n]helicenes (n=5 or 7) featuring a central, overcrowded alkene is described. The key cyclization step was based on an intramolecular McMurry reaction from the corresponding 1,5-diketones. Chiral stationary phase HPLC analysis and isomer separation indicate that each helicenic compound is constituted of three diastereoisomers at room temperature, i. e. the configurationally stable (R,R,P)/(S,S,M) pair of enantiomers and an apparently achiral compound resulting from the rapid interconversion between the (R,S,P) and (S,R,M) enantiomers. The partially saturated H6-fluoreno[n]helicenes are oxidatively aromatized to give an efficient access to the corresponding fluoreno[n]helicenes. The chiroptical properties (vibrational and electronic circular dichroism) of the chiral, enantiopure compounds have been measured and analyzed by quantum-chemical calculations, confirming their helicoidal nature. 相似文献
76.
Jeanne Erdmann 《Chemistry & biology》2012,19(10):1211-1212
77.
Dr. Keihann Yavari Dr. Wylliam Delaunay Dr. Nicolas De Rycke Thibault Reynaldo Dr. Paul Aillard Dr. Monika Srebro-Hooper Victoria Y. Chang Dr. Gilles Muller Dr. Denis Tondelier Bernard Geffroy Dr. Arnaud Voituriez Dr. Angela Marinetti Prof. Muriel Hissler Dr. Jeanne Crassous 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(20):5303-5310
Herein, the experimental physicochemical and chiroptical properties of a series of phosphahelicenes are reported, focusing on their UV/Vis absorption, luminescence, electronic circular dichroism, optical rotations, and circularly polarized luminescence. Furthermore, detailed analysis of absorption and ECD spectra performed with the help of quantum-chemical calculations allowed us to highlight general features of these helicenic phosphines. Finally, due to well-suited electrochemical properties and thermal stability, the systems were successfully used as emitters in organic light-emitting diodes. 相似文献
78.
Adriana M. Mihut Jérôme J. Crassous Holger Schmalz Matthias Ballauff 《Colloid and polymer science》2010,288(5):573-578
We present a systematic investigation of the crystallization and aggregation behavior of a poly(1,2-butadiene)-block-poly(ethylene oxide) diblock copolymer (PB-b-PEO) in n-heptane. n-Heptane is a poor solvent for PEO and at 70°C the block copolymer self-assembles into spherical micelles composed of a liquid
PEO core and a soluble PB corona. Time- and temperature-dependent light scattering experiments revealed that when crystallization
of the PEO cores is induced by cooling, the crystal morphology depends on the crystallization temperature (T
c
): Below 30°C, the high nucleation rate of the PEO core dictates the growth of the crystals by a fast aggregation of the micelles
into meander-like (branched) structures due to a depletion of the micelles at the growth front. Above 30°C the nucleation
rate is diminished and a relatively small crystal growth rate leads to the formation of twisted lamellae as imaged by scanning
force microscopy. All data demonstrate that the formation mechanism of the crystals through micellar aggregation is dictated
by two competitive effects, namely, by the nucleation and growth of the PEO core. 相似文献
79.
Crassous JJ Siebenbürger M Ballauff M Drechsler M Henrich O Fuchs M 《The Journal of chemical physics》2006,125(20):204906
We report on a comprehensive investigation of the flow behavior of colloidal thermosensitive core-shell particles at high densities. The particles consist of a solid core of poly(styrene) onto which a network of cross-linked poly(N-isopropylacrylamide) is affixed. Immersed in water the shell of these particles will swell if the temperature is low. Raising the temperature above 32 degrees C leads to a volume transition within this shell which leads to a marked shrinking of the shell. The particles have well-defined core-shell structure and a narrow size distribution. The remaining electrostatic interactions due to a small number of charges affixed to the core particles can be screened by adding 0.05M KCl to the suspensions. Below the lower critical solution temperature at 32 degrees C the particles are purely repulsive. Above this transition, a thermoreversible coagulation takes place. Lowering the temperature again leads to full dissociation of the aggregates formed by this process. The particles crystallize for effective volume fractions between 0.48 and 0.55. The crystallites can be molten by shear in order to reach a fluid sample again. The reduced shear stress measured in this metastable disordered state was found to be a unique function of the shear rate and the effective volume fraction. These reduced flow curves thus obtained can be described quantitatively by the theory of Fuchs and Cates [Phys. Rev. Lett. 89, 248304 (2002)] which is based on the mode-coupling theory of the glass transition. 相似文献
80.
Lassen PR Guy L Karame I Roisnel T Vanthuyne N Roussel C Cao X Lombardi R Crassous J Freedman TB Nafie LA 《Inorganic chemistry》2006,45(25):10230-10239
The infrared and vibrational circular dichroism (VCD) spectra of six chiral oxorhenium(V) complexes, bearing a hydrotris(1-pyrazolyl)borate (Tp) ligand, have been investigated. These complexes are promising candidates for observation of parity violation (symmetry breaking due to the weak nuclear force). New chiral oxorhenium complexes have been synthesized, namely, [TpReO(eta2-O(CH3)CH2CH2O-O,O)] (4a and 4b) diastereomers and [TpReO(eta2-N(CH3)CH2CH2O-N,O)] (5) and [TpReO(eta2-N(tBu)CH2CH2O-N,O)] (6) enantiomers. All compounds could be obtained in enantiomerically pure form by using either column chromatography or HPLC over chiral columns. VCD spectroscopy of these compounds and of [TpReO(eta2-N(CH3)CH(CH3)CH(Ph)O-N,O)] (2) and [TpReO(eta2-N(CH2)3CHCO2-N,O)] (3) (with chiral bidentate ligands derived, respectively, from ephedrine and proline) were studied. This allowed the absolute configuration determination of all compounds together with their conformational analysis, by comparing calculated and experimental spectra. This is the first VCD study of rhenium complexes which further demonstrates the applicability of VCD spectroscopy in determining the chirality of inorganic complexes. 相似文献