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131.
Di Antonio M Doria F Mella M Merli D Profumo A Freccero M 《The Journal of organic chemistry》2007,72(22):8354-8360
Mild activation of water-soluble naphthalene diimides (NDIs) as bisalkylating agents has been achieved by base catalysis and by chemical and electrochemical reductions. NDI activation by a single electron reduction represents a novelty in the field of activatable electrophiles. Under mild reduction, induced by S2O4(2-) in aqueous solution, the resulting NDI radical anion (NDI*-) undergoes a monomolecular fragmentation to yield a new transient species, where the NDI radical anion is tethered to a quinone methide moiety. The latter still retains electrophilic properties, reacting with amines, thiols, and ethyl vinyl ether. Owing to the NDI recognition properties, these results represent the first step toward selective and bioactivatable cross-linking agents. 相似文献
132.
Protection of lithium metal surfaces using chlorosilanes 总被引:1,自引:0,他引:1
Marchioni F Star K Menke E Buffeteau T Servant L Dunn B Wudl F 《Langmuir : the ACS journal of surfaces and colloids》2007,23(23):11597-11602
In this paper, we present a new approach for protecting metallic lithium surfaces based on a reaction between the thin native layer of lithium hydroxide present on the surface and various chlorosilane derivatives. The chemical composition of the resulting layer and the chemistry involved in layer formation were analyzed by polarization modulated infrared reflection absorption spectroscopy (PM-IRRAS), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray analysis (EDX). Spectroscopy shows the disappearance of surface hydroxide groups and the appearance of silicon and chloride on the lithium surface. Differential scanning calorimetry (DSC) and electrochemical impedance spectroscopy (EIS) show that this surface treatment protects the lithium from certain gas-phase reactions and is ionically conductive. 相似文献
133.
Charged spin-3/2 fields are coupled to an extended gauge model without the total suppression of the vector degrees of freedom which usually takes place as a consequence of simultaneously imposing the Maxwell and Rarita-Schwinger U(1) symmetries. 相似文献
134.
A Cecinato F Marino P Di Filippo L Lepore M Possanzini 《Journal of chromatography. A》1999,846(1-2):255-264
The distribution ratios of n-alkanes, polynuclear aromatic hydrocarbons (PAHs) and nitrated PAH components between fine and coarse fractions of soot has been investigated in downtown Rome through three field campaigns carried out at different times of the year. The preferential accumulation of almost all species investigated onto fine particles has been observed in all field experiments performed. Moreover, nitrated PAHs had varied distributions, according to the origin of their occurrence in the atmosphere; in fact, congeners of photochemical origin accumulated more in fine particles than those released by primary sources. 相似文献
135.
136.
Filippo Minutolo John A. Katzenellenbogen 《Angewandte Chemie (International ed. in English)》1999,38(11):1617-1620
A very stable heterogenized difunctional cyclopentadienyl-ring precursor , storable under ambient conditions, readily participates in the simultaneous formation of a η5 bond with a [fac-Re(CO)3]+ species and a σ bond with heteroatom (halides, carboxylates) or carbon nucleophiles (boronic acids) to produce halo-, acyloxy-, or carbon-substituted cyclopentadienyl–Re(CO)3 complexes in a one-pot reaction in yields of between 41 and 71 % [Eq. (1)]. No catalyst is required and unprotected (usually) sensitive functional groups are well tolerated. 相似文献
137.
Filippo Bianchi Falk K. Wittel Marcel Thielmann Pavel Trtik Hans J. Herrmann 《Transport in Porous Media》2018,122(1):169-184
In particle-laden flows through porous media, porosity and permeability are significantly affected by the deposition and erosion of particles. Experiments show that the permeability evolution of a porous medium with respect to a particle suspension is not smooth, but rather exhibits significant jumps followed by longer periods of continuous permeability decrease. Their origin seems to be related to internal flow path reorganization by avalanches of deposited material due to erosion inside the porous medium. We apply neutron tomography to resolve the spatiotemporal evolution of the pore space during clogging and unclogging to prove the hypothesis of flow path reorganization behind the permeability jumps. This mechanistic understanding of clogging phenomena is relevant for a number of applications from oil production to filters or suffosion as the mechanisms behind sinkhole formation. 相似文献
138.
139.
Pavone M Cimino P De Angelis F Barone V 《Journal of the American Chemical Society》2006,128(13):4338-4347
The nitrogen isotropic hyperfine coupling constant (hcc) and the g tensor of a prototypical spin probe (di-tert-butyl nitroxide, DTBN) in aqueous solution have been investigated by means of an integrated computational approach including Car-Parrinello molecular dynamics and quantum mechanical calculations involving a discrete-continuum embedding. The quantitative agreement between computed and experimental parameters fully validates our integrated approach. Decoupling of the structural, dynamical, and environmental contributions acting onto the spectral observables allows an unbiased judgment of the role played by different effects in determining the overall experimental observables and highlights the importance of finite-temperature vibrational averaging. Together with their intrinsic interest, our results pave the route toward more reliable interpretations of EPR parameters of complex systems of biological and technological relevance. 相似文献
140.
Murgia S Portesani F Ninham BW Monduzzi M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(30):7889-7898
The thermodynamically stable microemulsion and lamellar phases in the didodecyldimethylammonium bromide/water/n-decane ternary system were explored in the presence of NaBr to gain information on sodium ion-interface interactions. Experimental results, obtained by different NMR techniques, strongly suggest accumulation of sodium ions at the cationic interface. This apparently counterintuitive result is explained by invoking the dispersion potential experienced by the ions near the interface. A mechanism is proposed that can account for the dramatic shrinkage of the microemulsion phase region when an electrolyte is added. 相似文献