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231.
Elie CR Noujeim N Pardin C Schmitzer AR 《Chemical communications (Cambridge, England)》2011,47(6):1788-1790
We report the Cl(-) transport activity for three imidazolium-based transporters. We present significant findings regarding the use of α-cyclodextrin and cucurbit[7]uril macrocycles to form inclusion complexes with these salts and to inhibit their membrane activity. 相似文献
232.
Elie A. Moujaes Michel Abou Ghantous 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(8):178
Elastic exchange between two nearest Jahn-Teller (JT) centers in two or three dimensional dense crystals, can give an ordered macroscopic distortion known as cooperative JT effect (CJTE). A very diluted JT crystal does not show this effect. In the dynamic JT effect (DJTE), tunneling between different equivalent distorted wells has a pronounced influence on the CJTE. We investigate this phenomenon using a progressive increase in the concentration of these centers in the JT crystals, based on a bond percolation vector spin analogy technique within the framework of effective field theory (EFT). Mean field theory (MFT) was extensively used in previous studies of CJTE; however it neither includes correlation between JT centers in the lattice due to the complexity of the distortion field in the crystal nor the effect of tunneling between wells. We resort to an alternative procedure, by describing a JT center as a pseudo-spin vector \(\vec S\), induced to represent the degenerate JT-distorted states, where two nearest JT centers interact via an elastic exchange described by an Ising type spin interaction. The DJTE is considered to be similar to an elastic transverse field term in the Hamiltonian portraying the effect of tunneling between equivalent wells in the adiabatic potential energy surface (APES). We will be particularly discussing S = 1, S = 3/2 and S = 5/2 spin cases, where 2S + 1 wells in the APES are present and what JT systems they actually represent, with a percolative mechanism applied to the interactions between different JT centers. The different lattices are distinguished by their coordination numbers. Strong tunneling effects can suppress the CJTE and lead to a new state of criticality. Generalizations to higher spin systems will be obtained using a scaling technique. For the relevant distortions, we determine single site correlations, the macroscopic average distortion describing a structural phase transition and the elastic isothermal susceptibility as a function of temperature. The critical bond percolation threshold and the critical tunneling parameter are also obtained. 相似文献
233.
Lian-Kuet Chai Fatimah Elie Christine Jinang 《International journal of environmental analytical chemistry》2013,93(5):519-530
A simple extraction and cleanup procedure has been developed for the analysis of 24 organophosphorus (OP), organochlorine (OC) and pyrethroid (PY) pesticides in mineral and peat soils using modified QuEChERS method. The pesticides were extracted from the soil with acidified acetonitrile. The water was removed from the extract by salting out with sodium chloride and addition of magnesium sulfate. For OP pesticides, the extracts were cleaned up with 0.2 g of primary secondary amine packed in glass Pasteur pipette and determined by gas chromatography with flame photometric detector. For OC and PY pesticides, the extracts were cleaned up with 0.2 g of silica gel packed in a glass Pasteur pipette and determined by gas chromatography with electron capture detector. After the cleanup, the extracts had lower colour intensity and reduced matrix interferences. The recovery of the OP and OC pesticides for mineral and peat soils determined at 0.01–1.0 mg kg?1 fortification levels ranged from 79.0–120.0% and 82.2–117.6%, respectively. The detection limits for OP and OC pesticides were 0.001–0.01 and 0.002–0.005 mg kg?1, respectively. The recovery of the PY pesticides ranged from 87.5–111.7% at the detection limits of 0.002–0.010 mg kg?1. The relative standard deviations for all pesticides studied were below 10.8%. The modified method was simple, fast, and had utilized less reagents than the conventional methods. The method was applied to the determination of the pesticide residues in mineral and peat soil samples collected from the vegetable farms. 相似文献
234.
K. A. Milakin A. N. Korovin E. V. Moroz K. Levon A. Guiseppi‐Elie V. G. Sergeyev 《Electroanalysis》2013,25(5):1323-1330
Polyaniline (PANI)‐based sensor material for determination of ascorbic acid was synthesized by oxidative chemical polymerization of aniline on a screen‐printed carbon‐paste electrode. The influence of PANI chemical structure formed under various polymerization conditions on the sensor response was investigated. The presence of aniline dimer derivatives in PANI structure was found to induce significant improvement of the limit of detection and the linear dynamic range without a change in sensitivity. The sensor prepared by aniline polymerization in pH 7 buffer leading to the product containing mainly the aniline dimer‐based units showed the best detection limit of 0.1 µM. It was shown that the PANI‐based sensor could be used for ascorbic acid analysis in the presence of citrate and lactate as interfering ions. A quantitative determination of ascorbic acid concentration in beverages and vitamins was performed. 相似文献
235.
Jamal Nasser Elie About-jaudet Noel Collignon 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):171-179
Abstract Cycloalkylphosphonates 2 of different sizes (from cyclopropyl to cycloheptyl) bearing various functional groups Z in a position were synthesized by bis-alkylation of α-functional methylphosphonates 1 and Ω-dibromoalkanes in presence of base. The choice of the basic system is determined by the nature of Z. With powerful electron-withdrawing groups, NaH-THF/DMSO (Method A, for Z=CN, SO2R) or liquid-solid phase transfer process [Method B, for Z=COOR, P(O) (OEt)2] proved to be the more suitable systems. For Z=aryl or SR, lithium diisopropylamide is required to achieve the deprotonation. A wide range of new phosphonates were obtained in high yields on preparative scale. 相似文献
236.
Dr. Elie Geagea Ali Hamadeh Judicaël Jeannoutot Prof. Dr. Frank Palmino Nicolas Breault Prof. Dr. Alain Rochefort Dr. Samar Hajjar-Garreau Prof. Dr. Carmelo Pirri Prof. Dr. Christophe M. Thomas Dr. Frédéric Chérioux 《Chemphyschem》2023,24(15):e202300182
We demonstrate that the strong N2 bond can be efficiently dissociated at low pressure and ambient temperature on a Si(111)-7x7 surface. The reaction was experimentally investigated by scanning tunnelling microscopy and X-ray photoemission spectroscopy. Experimental and density functional theory results suggest that relatively low thermal energy collision of N2 with the surface can facilitate electron transfer from the Si(111)-7x7 surface to the π*-antibonding orbitals of N2 that significantly weaken the N2 bond. This activated N2 triple bond dissociation on the surface leads to the formation of a Si3N interface. 相似文献
237.
Catherine Grandin Elie About-Jaudet Noël Collignon Jean-Marc Denis Philippe Savignac 《Heteroatom Chemistry》1992,3(4):337-343
Diisopropyl 1,1-dichloroalkylphosphonates bearing various groups (alkyl, aryl, allyl, benzyl, phenylthiolate, trimethylsilyl) in the α-position were reduced to the corresponding primary 1,1-dichlorophosphines by the LiAlH4-AlCl3 system in diethyl ether. Subsequent dehydrochlorination with tertiary amines in the presence of trapping dipolar compounds (ethyl diazoacetate or n-hexylazide) led to the expected 1,2,4-diazaphospholes or 3H-1,2,3,4-triazaphospholes. 相似文献