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101.
Chavillon B Cario L Renaud A Tessier F Cheviré F Boujtita M Pellegrin Y Blart E Smeigh A Hammarström L Odobel F Jobic S 《Journal of the American Chemical Society》2012,134(1):464-470
Zinc oxide is considered as a very promising material for optoelectronics. However, to date, the difficulty in producing stable p-type ZnO is a bottleneck, which hinders the advent of ZnO-based devices. In that context, nitrogen-doped zinc oxide receives much attention. However, numerous reviews report the controversial character of p-type conductivity in N-doped ZnO, and recent theoretical contributions explain that N-doping alone cannot lead to p-typeness in Zn-rich ZnO. We report here that the ammonolysis at low temperature of ZnO(2) yields pure wurtzite-type N-doped ZnO nanoparticles with an extraordinarily large amount of Zn vacancies (up to 20%). Electrochemical and transient spectroscopy studies demonstrate that these Zn-poor nanoparticles exhibit a p-type conductivity that is stable over more than 2 years under ambient conditions. 相似文献
102.
FX Gallat AP Brogan Y Fichou N McGrath M Moulin M Härtlein J Combet J Wuttke S Mann G Zaccai CJ Jackson AW Perriman M Weik 《Journal of the American Chemical Society》2012,134(32):13168-13171
The observation of biological activity in solvent-free protein-polymer surfactant hybrids challenges the view of aqueous and nonaqueous solvents being unique promoters of protein dynamics linked to function. Here, we combine elastic incoherent neutron scattering and specific deuterium labeling to separately study protein and polymer motions in solvent-free hybrids. Myoglobin motions within the hybrid are found to closely resemble those of a hydrated protein, and motions of the polymer surfactant coating are similar to those of the hydration water, leading to the conclusion that the polymer surfactant coating plasticizes protein structures in a way similar to hydration water. 相似文献
103.
Dr. Bo Liu Dr. Thierry Roisnel Jean‐Paul Guégan Prof. Jean‐François Carpentier Dr. Yann Sarazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(20):6289-6301
The factors governing the stability and the reactivity towards cyclic esters of heteroleptic complexes of the large alkaline earth metals (Ae) have been probed. The synthesis and stability of a family of heteroleptic silylamido and alkoxide complexes of calcium [{LOi}Ca? Nu(thf)n] supported by mono‐anionic amino ether phenolate ligands (i=1, {LO1}?=4‐(tert‐butyl)‐2,6‐bis(morpholinomethyl)phenolate, Nu?=N(SiMe2H)2?, n=0, 4 ; i=2, {LO2}?=2,4‐di‐tert‐butyl‐6‐{[2‐(methoxymethyl)pyrrolidin‐1‐yl]methyl}phenolate, Nu?=N(SiMe2H)2?, n=0, 5 ; i=4, {LO4}?=2‐{[bis(2‐methoxyethyl)amino]methyl}‐4,6‐di‐tert‐butylphenolate, Nu?=N(SiMe2H)2?, n=1, 6 ; Nu?=HC?CCH2O?, n=0, 7 ) and those of the related [{LO3}Ae? N(SiMe2H)2] ({LO3}?=2‐[(1,4,7,10‐tetraoxa‐13‐azacyclopentadecan‐13‐yl)methyl]‐4,6‐di‐tert‐butylphenolate Ae=Ca, 1 ; Sr, 2 ; Ba, 3 ) have been investigated. The molecular structures of 1 , 2 , [( 4 )2], 6 , and [( 7 )2] have been determined by X‐ray diffraction. These highlight Ae???H? Si internal β‐agostic interactions, which play a key role in the stabilization of [{LOi}Ae? N(SiMe2H)2] complexes against ligand redistribution reactions, in contrast to regular [{LOi}Ae? N(SiMe3)2]. Pulse‐gradient spin‐echo (PGSE) NMR measurements showed that 1 , 4 , 6 , and 7 are monomeric in solution. Complexes 1 – 7 mediate the ring‐opening polymerization (ROP) of L ‐lactide highly efficiently, converting up to 5000 equivalents of monomer at 25 °C in a controlled fashion. In the immortal ROP performed with up to 100 equivalents of exogenous 9‐anthracenylmethanol or benzyl or propargyl alcohols as a transfer agent, the activity of the catalyst increased with the size of the metal ( 1 < 2 < 3 ). For Ca‐based complexes, the enhanced electron‐donating ability of the ancillary ligand favored catalyst activity ( 1 > 6 > 4 ≈ 5 ). The nature of the alcohol had little effect over the activity of the binary catalyst system 1 /ROH; in all cases, both the control and end‐group fidelity were excellent. In the living ROP of L ‐LA, the HC?CCH2O? initiating group (as in 7 ) proved superior to N(SiMe2H)2? or N(SiMe3)2? (as in 6 or [{LO4}Ca? N(SiMe3)2] ( B ), respectively). 相似文献
104.
105.
The reactions between several derivatives of 1-(3,5-dimethoxyphenyl)-prop-2-yn-1-ol and different ruthenium starting materials [i.e., RuCl?(PPh?)? and RuCl?(p-cymene)(L), where L is tricyclohexylphosphine di-t-butylmethylphosphine, dicyclohexylphenylphosphine, triisobutylphosphine, triisopropylphosphine, or tri-n-propylphosphine] are described. Several of these reactions allow for the easy, in-situ and atom-economic preparation of olefin metathesis catalysts. Organic precursor 1-(3,5-dimethoxyphenyl)-1-phenyl-prop-2-yn-1-ol led to the formation of active ruthenium indenylidene-ether complexes, while 1-(3,5-dimethoxyphenyl)-prop-2-yn-1-ol and 1-(3,5-dimethoxyphenyl)-1-methyl-prop-2-yn-1-ol did not. It was also found that a bulky and strong σ-donor phosphine ligand was required to impart good catalytic activity to the new ruthenium complexes. 相似文献
106.
Yann Ratieuville Philippe Viers Jean Alexandre Grard Durand 《Electrochemistry communications》2000,2(12):2727
As the resonance frequency of an oscillating quartz changes upon the deposition of a given mass to the crystal surface, it can be used as a very sensitive mass measuring device. Despite a growing interest in the use of electrochemical quartz crystal microbalance (EQCM), there is still no commercial available measurement cell which can satisfy all the conditions needed in electrochemical investigations. The design and characteristics of a new electrochemical cell adapted to EQCM measurements are presented. The sensitivity of the microbalance, which is determined by several calibration runs of silver electrodeposition is (183.2±2.9) Hz μg−1 cm2. This value, which is close to the theoretical one, confirms the validity of the system we have developed. The calibration procedure and the EQCM using range are then discussed. 相似文献
107.
Erwann Le Coz Ziyun Zhang Dr. Thierry Roisnel Prof. Dr. Luigi Cavallo Dr. Laura Falivene Prof. Dr. Jean-François Carpentier Dr. Yann Sarazin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(16):3535-3544
Two very rare cases of barium boryloxides, the homoleptic [Ba(OB{CH(SiMe3)2}2)2⋅C7H8] and the heteroleptic [{LONO4}BaOB{CH(SiMe3)2}2] stabilised by the multidentate aminoetherphenolate {LONO4}−, are presented, and their structural properties are discussed. The electron-deficient [Ba(OB{CH(SiMe3)2}2)2⋅C7H8] shows, in particular, resilient η6-coordination of the toluene molecule. Together with its amido parents [Ba{N(SiMe3)2}2⋅thf2] and [Ba{N(SiMe3)2}2]2, this complex catalyses the fast and chemoselective dehydrocoupling of borinic acids R2BOH and hydrosilanes HSiR′3, yielding borasiloxanes R2BOSiR′3 in a controlled fashion. The assessment of substrate scope indicates that, for now, the reaction is limited to bulky borinic acids. Kinetic analysis shows that the rate-limiting step of the catalytic manifold traverses a dinuclear transition state. A detailed mechanistic scenario is proposed on the basis of DFT computations, the results of which are fully consistent with experimental data. It consists of a stepwise process with rate-determining nucleophilic attack of a metal-bound O-atom onto the incoming hydrosilane, involving throughout dinuclear catalytically active species. 相似文献
108.
Yann Bourne-Branchu Dr. Corinne Gosmini Dr. Grégory Danoun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(11):2663-2674
Since 2015, the use of amides as electrophilic partners in cross-coupling reactions has experienced exponential growth. Diverse amide derivatives have been studied and among them N-Boc-amides have shown good activities towards various cross-coupling reactions and presents, in our view, an important synthetic usefulness. This review describes the recent developments of these chemical transformations involving N-Boc-amides. 相似文献
109.
Dr. Eduardo Ferreira Molina Natana Aparecida Martins de Jesus Serge Paofai Dr. Peter Hammer Dr. Maria Amela-Cortes Dr. Malo Robin Dr. Stephane Cordier Dr. Yann Molard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(67):15248-15251
Hybrid materials that combine diureasil matrices and octahedral molybdenum clusters have been synthesized to design lead-, cadmium- and rare-earth-free emitters for lighting or optoelectronic applications. This association leads to homogeneous and stable hybrids, for which the emission color can be tailored in the entire visible range, including white light; this is thanks to effective energy transfers from the host to the nanocluster. 相似文献
110.
Emmanuel Nolot Yann Mazel Jean-Paul Barnes Chiara Sabbione Gabriele Navarro Agnes Tempez Sébastien Legendre 《Surface and interface analysis : SIA》2020,52(12):895-899
We demonstrate the potential of using plasma profiling time-of-flight mass spectrometry (PP-TOFMS) to accelerate process developments for phase-change random access memory (PCRAM) applications, which require advanced materials with composition-driven properties. We assess the performances of PP-TOFMS for the chemical depth-profiling of GeSbTe phase change materials, first after deposition steps to investigate the top surface layer and the incorporation of silicon into the amorphous matrix, then after the thermal annealing step to refine in situ capping strategies, and finally in close loop with etching process steps. Comparison of reference-free semiquantitative PP-TOFMS analysis based on ion beam ratio with Rutherford backscattering spectrometry shows remarkable agreement (~10% relative). PP-TOFMS proves to be a fast screening tool, which allows process monitoring and selection of samples that indeed need more complex analysis. 相似文献