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81.
Dr. Sarah Desmons Yu Zhou Dr. Dan Zhang Dr. Carlos Jarava-Barrera Dr. Anaïs Coffinet Dr. Antoine Simonneau Dr. Laure Vendier Prof. Dr. Gen Luo Dr. Sébastien Bontemps 《European journal of organic chemistry》2023,26(30):e202300525
The hydroboration of CO2 into bis(boryl)acetal (BBA) compounds is an important transformation, since it enabled to selectively reduce CO2 by 4e- and to subsequently use the BBA compounds as C1 and Cn sources. However, the influence of the nature of the boryl moieties on the reactivity of BBA compounds has not been evaluated so far. In the present study, four BBA compounds – including two new ones – were reacted with 2,6-diisopropylaniline to afford the expected imine. Significant differences in the rate of the reaction from minutes to weeks have been observed depending on the BBA used, showing the importance of the nature of the boryl moieties. Theoretical investigations enabled to propose a mechanism involving the addition of the aniline to the BBA as the rate-determining step and to determine that the steric hindrance of the BBA compounds is the main factor driving the rate of this condensation reaction. 相似文献
82.
Synthesis and Thermophysical Properties of Ether‐Functionalized Sulfonium Ionic Liquids as Potential Electrolytes for Electrochemical Applications
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Dr. Erwan Coadou Dr. Peter Goodrich Alex R. Neale Dr. Laure Timperman Prof. Christopher Hardacre Dr. Johan Jacquemin Prof. Mérièm Anouti 《Chemphyschem》2016,17(23):3992-4002
During this work, a novel series of hydrophobic room temperature ionic liquids (ILs) based on five ether functionalized sulfonium cations bearing the bis{(trifluoromethyl)sulfonyl}imide, [NTf2]? anion were synthesized and characterized. Their physicochemical properties, such as density, viscosity and ionic conductivity, electrochemical window, along with thermal properties including phase transition behavior and decomposition temperature, have been measured. All of these ILs showed large liquid range temperature, low viscosity, and good conductivity. Additionally, by combining DFT calculations along with electrochemical characterization it appears that these novel ILs show good electrochemical stability windows, suitable for the potential application as electrolyte materials in electrochemical energy storage devices. 相似文献
83.
A new PN2S ligand, N-[2-(diphenylphosphino)phenyl]-2-[(S-trityl)acetylamino]ethanamide [Ph-P(Ph2)N2S(Trt)], was synthesised and reacted with ReV precursors. The reaction of both tritylated and detritylated ligands with ReOCl3(PPh3)2 gave the same expected neutral complex [ReO{Ph-P(Ph2)N2S}] (4) in good yield. An unexpected neutral and diamagnetic species, [ReN{Ph-P(Ph2)N2S(Trt)}] (5), has been isolated during the complexation of the tritylated ligand with ReNCl2(PPh3)2. The complexes, characterized by classical spectroscopic methods and X-ray analysis for 4, are the first examples of neutral semi-rigid-PN2S rhenium(V) complexes. 相似文献
84.
85.
Clifford MN Lopez V Poquet L Williamson G Kuhnert N 《Rapid communications in mass spectrometry : RCM》2007,21(13):2014-2018
We report a systematic investigation of the effects and structural requirements for ion suppression in negative ion mode electrospray ionisation mass spectrometry of a series of carboxylic acids and present a structural model rationalising ion suppression effects. 相似文献
86.
87.
Christian Amatore Anny Jutand Laure Mensah 《Journal of organometallic chemistry》2007,692(7):1457-1464
Specific chiral ligands have been designed by Trost et al. to perform enantioselective Pd-catalyzed allylic alkylations. It is shown that the Pd(0) complex formed by addition of the Trost ligand (4) to Pd0(dba)2 is not stable in most solvents (acetone, DMF, CH2Cl2). Indeed, Pd0(dba)(4) leads to the formation of a stable PdII complex 5 (X-ray structure), likely by activation of the two N-H bonds of the ligand by the Pd0 centre. The formation of the PdII complex competes with the reaction of Pd0(4) with (E)-PhCHCH-CH(OAc)-Ph, excluding any investigation of the kinetics of the latter reaction. The ionization steps from intermediate (η2-PhCHCH-CH(OAc)-Ph)Pd0(4) were found to be very slow. The cationic P,P complex [(η3-Ph-CH-CH-CH-Ph)Pd(4)]+, expected to be generated by addition of 2 equiv. of 4 to the precursor [(η3-Ph-CH-CH-CH-Ph)Pd(μ-Cl)]2, in the presence of a chloride scavenger, leads to a complex mixture whereas addition of 1 equiv. of 4 affords a stable bis-cationic PdII complex {[(η3-Ph-CH-CH-CH-Ph)Pd]2(4)]}2+, (X-ray structure) via a P,O complexation of each allyl-Pd moieties. This dissymmetric P,O coordination will favour the enantioselectivity of Pd-catalyzed allylic alkylation of (E)-PhCHCH-CH(OAc)-Ph by the control of the regioselectivity of the nucleophilic attack onto the allylic ligand which is responsible of the enantioselectivity of the overall catalytic reaction. 相似文献
88.
89.
To gain better insight into the influence of the anion size and symmetry on the transport properties and thermal stability of an electrolyte based on lithium(fluorosulfonyl)(trifluoromethanesulfonyl)-imide(FTFSI)salt,we performed the physical and electrochemical characterization of an electrolyte based on FTFSI incorporated in standard binary(3 EC/7 EMC)and ternary(EC/PC/3 DMC)alkylcarbonate mixtures.By applying the Jones-Dole-Kaminsky(JDK),Eyring and Arrhenius empirical models to the electrolyte viscosity we show that the activation enthalpy and entropy energy barriers(ΔH≠,ΔS≠)for viscous flow are between 12 and 15 kJ·mol-1.They are strongly dependent on the solvent nature and are significantly lower than their symmetric anions LiFSI and LiTFSI(19-20 kJ·mol-1)in the binary mixture.Furthermore,the hydrodynamic radius,rs,calculated by JDK,and the ionicity behavior illustrated by the Walden role,showed that the FTFSI anion is outside the solvation sphere(rs>0.6 nm)which is smaller in the case of an EC/EMC solvent base.In the 3 EC/7 EMC solvent mixture,LiFTFSI is less conductive than in the ternary mixture i.e.,σmax=8.9 mS cm-1 at Cmax=1.1 mol L-1 for 3 EC/7 EMC and,σmax=10.5 mS cm-1 at max=0.7 mol L-1 for EC/PC/3 DMC,due to a strong solvation and a greater association of FTFSI ions in the binary solvent mixture.The thermal stability of FTFSI based electrolytes was determined by the shift of the evaporation temperature of the volatile solvents(DMC,EMC)in the presence of salt,towards the higher temperatures.This feature is visible on the thermograms obtained by DSC both with the liquid electrolyte and with charged LMO cathodes in presence of electrolytes.The consequences of these properties on the electrochemical behavior of a graphite(Gr)half-cell,a lithium metal(Li)anode and a manganese lithium oxide(LMO)cathode demonstrated on the one hand the formation of a thick solid electrolyte interphase(SEI)on graphite that consumed a significant amount of lithium i.e.,18%of total capacity of the first charge.Furthermore,LiFTFSI delivered 95%of the initial capacity C=360 mAh g-1 at C/10 with EC/PC/3 DMC versus 91%when it was combined with 3 EC/7 EMC C=348 mAh g-1,while the capacities obtained for LiTFSI in EC/PC/3 DMC were the lowest(C=275 mAh g-1)compared to those of the other salts.After 10 cycles,the capacity loss at C/20 is<2%for LiFSI and LiFTFSI with the two solvent mixtures.On the other hand,manganese dissolution from LMO as well as current collector corrosion were confirmed by post-mortem examination of opened coin cells.The incompatibility of the LMO cathode with an electrolyte based on FTFSI was confirmed by the position of the decomposition peak of charged LMO in contact with this electrolyte observed by DSC These results demonstrate that the nature of the anion as well as the composition of the solvent considerably influence the performance of imide-based lithium salts both on the anode,but especially on the high voltage cathode. 相似文献
90.
A multi residue analysis was developed for screening, quantification and confirmation of 36 priority organic compounds included in the 2000/60/EC European Water Framework Directive. The compounds analyzed included 19 pesticides, 8 PAH, 5 endocrine-disruptors and 4 organochlorine compounds. The method was developed in three steps. First, automated off-line solid-phase extraction using Strata X cartridges was optimized to trap simultaneously the 36 studied compounds. Second, the more volatile compounds were analysed by gas chromatography coupled to mass spectrometry with electron impact ionisation in selected ion monitoring mode (SIM). Third, the last 20 compounds were detected and quantified, in one run, by liquid chromatography coupled to fluorescence detector and tandem mass spectrometry. The excellent selectivity and sensitivity allowed us satisfactory quantification and confirmation at levels as low as 0.2-67 ng L−1 with recoveries between 59 and 105%. Such methodology was then applied to French surface waters: all the waters present organic contaminants, and their concentration varied according to the origin and nature of substances. 相似文献