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81.
Campanelli Anna Rita Domenicano Aldo Macchiagodena Marina Ramondo Fabio 《Structural chemistry》2011,22(5):1131-1141
Reference values of the structural substituent parameters, S
E and S
R, measuring the electronegativity and resonance effects, respectively, of functional groups (Campanelli et al. J Phys Chem
A 107:6429–6440, 2003) have been determined from the benzene ring geometries of 100 Ph–X species, including different conformations of the same
molecule. Geometries have been obtained by quantum chemical calculations at the HF/6-31G*, HF/6-311++G**, and B3LYP/6-311++G**
levels of theory. The substituent parameters from HF/6-311++G** calculations are in close agreement with those determined
at the HF/6-31G* level. Using the B3LYP density functional yields S
E and S
R values which—in general—correlate well with the corresponding HF values. Exceptions occur with some charged groups, and,
in the case of S
E, with a few dipolar groups having very high or low electronegativities. S
R values from B3LYP calculations are about 22% smaller than the corresponding HF values. The variations of the benzene ring
geometry caused by electronegativity, resonance, and steric effects are illustrated in some detail. 相似文献
82.
Capriotti AL Caracciolo G Cavaliere C Crescenzi C Pozzi D Laganà A 《Analytical and bioanalytical chemistry》2011,401(4):1195-1202
The knowledge about the interaction between plasma proteins and nanocarriers employed for in vivo delivery is fundamental
to understand their biodistribution. Protein adsorption onto nanoparticle surface (protein corona) is strongly affected by
vector surface characteristics. In general, the primary interaction is thought to be electrostatic, thus surface charge of
carrier is supposed to play a central role in protein adsorption. Because protein corona composition can be critical in modifying
the interactive surface that is recognized by cells, characterizing its formation onto lipid particles may serve as a fundamental
predictive model for the in vivo efficiency of a lipidic vector. In the present work, protein coronas adsorbed onto three
differently charged cationic liposome formulations were compared by a shotgun proteomic approach based on nano-liquid chromatography–high-resolution
mass spectrometry. About 130 proteins were identified in each corona, with only small differences between the different cationic
liposome formulations. However, this study could be useful for the future controlled design of colloidal drug carriers and
possibly in the controlled creation of biocompatible surfaces of other devices that come into contact with proteins into body
fluids. 相似文献
83.
Aldo de Luca 《Proceedings of the Steklov Institute of Mathematics》2011,274(1):124-135
This paper is a survey of several results of combinatorial nature which have been obtained starting from a palindromization
map on a free monoid A* introduced by the author in 1997 in the case of a binary alphabet and, successively, generalized by other authors for arbitrary
finite alphabets. If one extends the action of the palindromization map to infinite words, one can generate the class of all
standard episturmian words, which includes standard Sturmian words and Arnoux-Rauzy words. In this framework, an essential
role is played by the class of palindromic prefixes of all standard episturmian words called epicentral words. These words
are precisely the images of A* under the palindromization map. Epicentral words have several different representations and satisfy interesting combinatorial
properties. A further extension of the palindromization map to a t9-palindromization map, where t9 is an arbitrary involutory antimorphism of A*, is also briefly discussed. 相似文献
84.
Lavergne A Zhu Y Pizzino A Molinier V Aubry JM 《Journal of colloid and interface science》2011,360(2):645-653
Two agro-based anionic surfactants containing an isosorbide moiety have been synthesized and their amphiphilic properties evaluated. Since isosorbide is now considered as an important platform chemical of the starch industry, these compounds could represent bio-sourced alternatives to the alkyl ether sulfates (notably lauryl ether sulfate, LES) that are based on petroleum-derived ethylene oxides. As isosorbide is an asymmetric diol, two isomers can be prepared (2-O-dodecyl isosorbide sulfate and 5-O-dodecyl isosorbide sulfate) that show significantly different aqueous properties as regards to their Krafft temperatures and critical micellar concentrations. 5-O-dodecyl isosorbide sulfate is the most soluble and the most efficient surfactant. It possesses a much lower critical micelle concentration (cmc) than sodium dodecyl sulfate, SDS, leading to comparable foaming properties with a three times lower concentration. Its behavior compares well with the one of pure diethoxylated dodecyl sulfate that has also been prepared and evaluated in this work. 相似文献
85.
Mattioli G Risch M Amore Bonapasta A Dau H Guidoni L 《Physical chemistry chemical physics : PCCP》2011,13(34):15437-15441
Ab initio molecular dynamics simulations of a recently proposed cobalt-based catalyst for water oxidation provide insight into the properties of protons at the water/oxide interface. Calculations and X-ray absorption spectroscopy data indicate a cubane-like structure of the catalyst, support the occurrence of protonated μ(2)-O atoms, suggest deprotonated μ(3)-O atoms and the presence of sites promoting low-barrier hydrogen bonds. 相似文献
86.
Giorgio Della Sala Antonietta Artillo Aldo Spinella 《Journal of organometallic chemistry》2007,692(8):1623-1627
A study on the oxidation of Fischer tungsten-carbene uracil complexes has been carried out. Several commonly used oxidants gave results strongly influenced by the presence of substituent on nitrogen atoms. In particular, usual oxidants failed in the oxidation of 3-alkyl uracil carbene complexes. Finally, we showed that t-butyl hydroperoxide is able to oxidize successfully also 3-alkyl uracil carbene complexes and can be used as a good alternative to the other methods. 相似文献
87.
This paper provides an insight into dimension analysis from time series. In particular, we propose a procedure based on the pointwise dimension in order to extract, for each embedding dimension, the subset of points in the phase space (and the corresponding ones in the time series) which give rise to the scaling behaviour. We may consider the output time series as the result of a filtering process, based on correlations of points in the phase-space domain. Furthermore, the procedure gives the statistics of points which determine the scaling behaviour. 相似文献
88.
Aldo Procacci Emmanuel Pereira Armando G. M. Neves Domingos H. U. Marchetti 《Journal of statistical physics》1997,87(3-4):877-889
We study the Mayer series of the two-dimensional dipole gas in the high-temperature, low-density regime. Without performing any multiscale analysis, we obtain bounds showing that the Mayer coefficients are finite in the thermodynamic limit. These bounds are obtained by exploiting a particular partial symmetry of the interaction (which we nameO-symmetry), already used in some problems related to the two-dimensional Coulomb gas. By direct bounds on some Mayer graphs we also conjecture that any technique based uniquely on theO-symmetry will not be sufficient to prove analyticity of the series. 相似文献
89.
90.
Communicated by Dominique Perrin 相似文献