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51.
Antonino Arcoria Emanuele Maccarone Gaetano A. Tomaselli Rosario Calí Salvatore Currieri 《Journal of heterocyclic chemistry》1975,12(2):333-335
The second order rate constants k2 and the activation parameters for the reaction of 2-thiophenesulfonyl chloride with aniline together with solution enthalpies of the reactants have been measured in methanol, ethanol, 2-propanol, acetonitrile and acetone. The reaction rates are slower in dipolar aprotic solvents than in protic ones due to a remarkable activation negative entropy. The rate constants k2 are correlated with empirical solvent polarity parameters. The data seem in accord with a SAN reaction mechanism. 相似文献
52.
Silvia Bonettini Emanuele Galligani Valeria Ruggiero 《Computational Optimization and Applications》2007,37(1):1-34
This paper deals with the solution of nonlinear programming problems arising from elliptic control problems by an interior
point scheme. At each step of the scheme, we have to solve a large scale symmetric and indefinite system; inner iterative
solvers, with an adaptive stopping rule, can be used in order to avoid unnecessary inner iterations, especially when the current
outer iterate is far from the solution.
In this work, we analyse the method of multipliers and the preconditioned conjugate gradient method as inner solvers for interior
point schemes. We discuss the convergence of the whole approach, the implementation details and report the results of numerical
experimentation on a set of large scale test problems arising from the discretization of elliptic control problems. A comparison
with other interior point codes is also reported.
This research was supported by the Italian Ministry for Education, University and Research (MIUR) projects: FIRB Project:
“Parallel Nonlinear Numerical Optimization PN
2
O” (grant n. RBAU01JYPN, ) and COFIN/PRIN04 Project “Numerical Methods and Mathematical Software for Applications” (grant n. 2004012559, ). 相似文献
53.
Emanuele Galligani 《Annali dell'Universita di Ferrara》2002,48(1):99-117
Sunto L’applicazione di noti metodi che utilizzano funzioni di tipo blending per la costruzione di funzioni bivariate C1 per l’interpolazione di dati, richiede la conoscenza delle derivate parziali del primo ordine ai vertici di una triangolazione
sottostante. In questo lavoro consideriamo il metodo proposto da Nielson, che consiste nel calcolare stime delle derivate
parziali del primo ordine minimizzando un opportuno funzionale quadratico, caratterizzato da parametri di tensione non negativi.
Scopo del lavoro è l’analisi di alcune proprietà particolari di questo funzionale per la costruzione di algoritmi efficienti
e robusti per la determinazione delle stime suddette delle derivate quando si ha a che fare con insiemi di dati di grandi
dimensioni.
Abstract
The application of widely known blending methods for constructingC
1 bivariate functions interpolating scattered data requires the knowledge of the partial derivatives of first order at the
vertices of an underlying triangulation. In this paper we consider the method proposed by Nielson that consists in computing
estimates of the first order partial derivatives by minimizing an appropriate quadratic functional, characterized by nonnegative
tension parameters. The aim of the paper is to analyse some peculiar properties of this functional in order to construct robust
and efficient algorithms for determining the above estimates of the derivatives when we are concerned with extremely large
data sets.
相似文献
54.
Mariagrazia Bianchi David Chillag Mark L. Lewis Emanuele Pacifici 《Proceedings of the American Mathematical Society》2007,135(3):671-676
Let be a finite group, and write for the set of degrees of irreducible characters of . We define to be the graph whose vertex set is , and there is an edge between and if . We prove that if is a complete graph, then is a solvable group.
55.
We prove surface and volume mean value formulas for classical solutions to uniformly parabolic equations in the divergence form with low regularity of the coefficients. We then use them to prove the parabolic strong maximum principle and the parabolic Harnack inequality. We emphasize that our results only rely on the classical theory, and our arguments follow the lines used in the original theory of harmonic functions. We provide two proofs relying on two different formulations of the divergence theorem, one stated for sets with almost C1-boundary, the other stated for sets with finite perimeter. 相似文献
56.
Dr. Alessandra Alberti Dr. Ioannis Deretzis Dr. Giovanna Pellegrino Dr. Corrado Bongiorno Dr. Emanuele Smecca Dr. Giovanni Mannino Dr. Filippo Giannazzo Prof. Guglielmo Guido Condorelli Dr. Nobuya Sakai Prof. Tsutomu Miyasaka Dr. Corrado Spinella Dr. Antonino La Magna 《Chemphyschem》2015,16(14):3064-3071
We investigate the degradation path of MAPbI3 (MA=methylammonium) films over flat TiO2 substrates at room temperature by means of X‐ray diffraction, spectroscopic ellipsometry, X‐ray photoelectron spectroscopy, and high‐resolution transmission electron microscopy. The degradation dynamics is found to be similar in air and under vacuum conditions, which leads to the conclusion that the occurrence of intrinsic thermodynamic mechanisms is not necessarily linked to humidity. The process has an early stage, which drives the starting tetragonal lattice in the direction of a cubic atomic arrangement. This early stage is followed by a phase change towards PbI2. We describe how this degradation product is structurally coupled with the original MAPbI3 lattice through the orientation of its constituent PbI6 octahedra. Our results suggest a slight octahedral rearrangement after volatilization of HI+CH3NH2 or MAI, with a relatively low energy cost. Our experiments also clarify why reducing the interfaces and internal defects in the perovskite lattice enhances the stability of the material. 相似文献
57.
Emanuele Miserazzi Mario Alessandro SpottiRoberto Profeta Simone SpadaArnaldo Nalin Elisa MoroDaniele Andreotti 《Tetrahedron letters》2011,52(3):448-452
An interesting and surprising rearrangement was observed during the reaction of 4-N-benzyl piperazinone derivatives with Lawesson’s reagent as a thionating agent. Investigation into the possible mechanism responsible for these results is reported herein. 相似文献
58.
Rio-Echevarria IM Tavano R Causin V Papini E Mancin F Moretto A 《Journal of the American Chemical Society》2011,133(1):8-11
The stabilizing action of C(α)-tetrasubstituted α-amino acids inserted into a sequence of short peptides allowed for the first time the preparation of water-soluble nanoparticles of different materials coated with a helix-structured undecapeptide. This peptide coating strongly favors nanoparticle uptake by human immune system cells. 相似文献
59.
Euterpio MA Cavaliere C Capriotti AL Crescenzi C 《Analytical and bioanalytical chemistry》2011,401(9):2977-2985
Pressurized hot water extraction (PHWE, also known as subcritical water extraction) is commonly considered to be an environmentally
friendly extraction technique that could potentially replace traditional methods that use organic solvents. Unfortunately,
the applicability of this technique is often limited by the very low water solubility of the target compounds, even at high
temperatures. In this paper, the scope for broadening the applicability of PHWE by adjusting the pH of the water used in the
extraction is demonstrated in the extraction of curcumin (which exhibits very limited water solubility) from untreated turmeric
(Curcuma longa L.) rhizomes. Although poor extraction yields were obtained, even at high temperatures when using degassed water or neutral
phosphate buffer as the extraction medium, yields exceeding those obtained by Soxhlet extraction were achieved using highly
acidic pH buffers due to curcumin protonation. The influence of the temperature, pH, and buffer concentration on the extraction
yield were investigated in detail by means of a series of designed experiments. Optimized conditions for the extraction of
curcumin from turmeric by PHWE were estimated at 197 °C using 62 g/L buffer concentration at pH 1.6. The relationships between
these variables were subjected to statistical analysis using response surface methodology. 相似文献
60.
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