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11.
We develop a quantitative method of analysis of EEG records. The method is based on the wavelet analysis of the record and on the capability of the Jensen–Shannon divergence (JSD) to identify dynamical changes in a time series. The JSD is a measure of distance between probability distributions. Therefore for its evaluation it is necessary to define a (time dependent) probability distribution along the record. We define this probability distribution from the wavelet decomposition of the associated time series. The wavelet JSD provides information about dynamical changes in the scales and can be considered a complementary methodology reported earlier [O.A. Rosso, S. Blanco, A. Rabinowicz, Signal Processing 86 (2003) 1275; O.A. Rosso, S. Blanco, J. Yordanova, V. Kolev, A. Figliola, M. Schürmann, E. Ba?ar, J. Neurosci. Methods 105 (2001) 65; O.A. Rosso, M.T. Martin, A. Figliola, K. Keller, A. Plastino, J. Neurosci. Methods 153 (2006) 163]. In the present study we have demonstrated it by analyzing EEG signal of tonic–clonic epileptic seizures applying the JSD method. The display of the JSD curves enables easy comparison of frequency band component dynamics. This would, in turn, promise easy and successful comparison of the EEG records from various scalp locations of the brain. 相似文献
12.
V. I. Burenkov P. D. Lamberti M. Lanza de Cristoforis 《Journal of Mathematical Sciences》2008,149(4):1417-1452
The survey is devoted to spectral stability problems for uniformly elliptic differential operators under the variation of
the domain and to the accompanying estimates for the difference of the eigenvalues. Two approaches to the problem are discussed
in detail. In the first one it is assumed that the domain is transformed by means of a transformation of a certain class,
and the spectral stability with respect to this transformation is investigated. The second approach is based on the notion
of a transition operator and allows direct comparison of the eigenvalues on domains which are close in that or another sense.
__________
Translated from Sovremennaya Matematika. Fundamental’nye Napravleniya (Contemporary Mathematics. Fundamental Directions),
Vol. 15, Differential and Functional Differential Equations. Part 1, 2006. 相似文献
13.
A method of constructing a family of regular rotating disks as sources of the Kerr metric is discussed. The algebraic type of the energy-momentum tensor is analyzed, and it is found that none of the disks satisfies the dominant energy condition and, in some cases, even the weak energy condition is violated. Therefore, if the constructed family includes the totality of sources for the Kerr metric with a disk-like topology, then any physically satisfactory source will not have a disk structure. 相似文献
14.
The large unit cells, the enormous flexibility and variation in structural motifs of MOFs represent a big challenge in the characterization of MOF materials, particularly in cases where single crystal diffraction data are not available. In this critical review it is shown that in cases where only powder diffraction data are available additional structural information, particularly regarding local coordination within the inorganic cluster, are often mandatory in order to solve the structure. There are also cases where the inorganic cluster does not follow the symmetry of the overall structure. In such cases diffraction techniques will just "see" an average structure, missing the local structure: a lack that may be critical for understanding the specific properties of the material. In both cases, EXAFS spectroscopy is the tool that provides complementary structural information on the inorganic cluster and the way it binds to the ligand. Selected examples will show how EXAFS will be relevant in: (i) confirming the structure obtained from diffraction refinements; (ii) highlighting that the inorganic cornerstone has a lower symmetry with respect to that of the organic framework; (iii) obtaining the local structure of the inorganic cluster in the desolvated material when desolvation causes a partial loss of long range order; (iv) obtaining the local structure of the inorganic cluster in the desolvated material after coordination of a probe (or reactant) molecule, including cluster deformation upon molecule coordination and metal-molecule binding distance; (v) evidencing the presence of impurities in the form of amorphous extra-phases (339 references). 相似文献
15.
Salassa L Borfecchia E Ruiu T Garino C Gianolio D Gobetto R Sadler PJ Cammarata M Wulff M Lamberti C 《Inorganic chemistry》2010,49(23):11240-11248
Determination of transient structures in light-induced processes is a challenging goal for time-resolved techniques. Such techniques are becoming successful in detecting ultrafast structural changes in molecules and do not require the presence of probe-like groups. Here, we demonstrate that TR-WAXS (Time-Resolved Wide Angle X-ray Scattering) can be successfully employed to study the photochemistry of cis-[Ru(bpy)(2)(py)(2)]Cl(2), a mononuclear ruthenium complex of interest in the field of photoactivatable anticancer agents. TR-WAXS is able to detect the release of a pyridine ligand and the coordination of a solvent molecule on a faster timescale than 800 ns of laser excitation. The direct measurement of the photodissociation of pyridine is a major advance in the field of time-resolved techniques allowing detection, for the first time, of the release of a multiatomic ligand formed by low Z atoms. These data demonstrate that TR-WAXS is a powerful technique for studying rapid ligand substitution processes involving photoactive metal complexes of biological interest. 相似文献
16.
Mina Mazzeo Marina Lamberti Ilaria D'Auria Stefano Milione Jonas C. Peters Claudio Pellecchia 《Journal of polymer science. Part A, Polymer chemistry》2010,48(6):1374-1382
New Group 3 metal complexes of the type [LM(CH2SiMe3)2(THF)n] supported by tridentate phosphido‐diphosphine ligands [(o‐C6H4PR2) 2 PH; L1‐H : R = iPr; L2‐H : R = Ph] have been synthesized by reaction of L1‐H and L2‐H with [M(CH2SiMe3)3(THF)2)] (M = Y and Sc). All the new complexes [(o‐C6H4PR2) 2 PM(CH2SiMe3)2(THF)n] [M = Y, R = iPr (1), R = Ph (2); M = Sc, R = iPr (3), R = Ph (4)] were studied as initiators for the ring opening polymerization of lactide. The yttrium complexes ( 1 and 2 ) exhibited high activity and good polymerization control, shown by the linear fits in the plot of number‐averaged molecular weight (Mn) versus the percentage conversion and versus the monomer/initiator ratio and by the low polydispersity index values. Interestingly, very good molar‐mass control was observed even when L ‐Lactide was polymerized in the absence of solvent at 130 °C. A good molar‐mass control but lower activities were observed in the polymerization reaction of lactide promoted by the analogous scandium complexes 3 and 4 . © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1374–1382, 2010 相似文献
17.
In this work, the heat transfer phenomena taking place during the cooling of thin films of crystallizable polymers were analyzed.
The thermal histories, as recorded during experimental cooling runs carried out at various cooling rates, were compared with
the predictions of a general purpose numerical code, which was resulted able to capture all the main features of the process.
Thus, the conditions which allow homogeneous cooling (negligible temperature gradient within the sample) or homogeneous cooling
history (the same cooling history for all the positions within the sample) were predicted by the simulation code. 相似文献
18.
Grain shear flow in a rotating drum 总被引:2,自引:0,他引:2
In the present paper we report on the experimental activities carried out on a rotating drum partially filled with grains
or glass beads. The experiments give information about rheology through velocity profiles and through the velocity covariance
tensor structure. We used a LDV system to measure the velocity of the grains at several points along three vertical sections.
The data were also used to obtain the grain volume concentration, with encouraging results. Instantaneous velocity data were
elaborated in order to obtain velocity and pseudotemperature profiles for all the experiments; for a subset of the experiments
a large set of data were elaborated to obtain the velocity covariance. The velocity covariance is not collinear with the rate
of deformation tensor. An attempt to justify the rotation of the tensor axes as a consequence of the kinetically induced anisotropy
and of some free surface perturbations slowly moving upstream was partially successful.
Received: 23 April 1999 / Accepted: 15 July 2001 相似文献
19.
C. Lamberti A. Antolini S. Bianchi A. Castelli M. Dellagiovanna 《Zeitschrift für Physik B Condensed Matter》1996,100(2):195-198
GaAs technology for microwave devices (MESFET and MMIC) has received a significant improvement by ion implantation of silicon to form n-type active channel regions. Owing to amphoteric behaviour of silicon in GaAs, different activation of the implanted species can be obtained, depending on the post-implantation annealing treatment. In this paper we describe the results of the influence of rapid thermal annealing on implanted GaAs and using 4 K photoluminescence spectroscopy we identify the corresponding species (SiAS and SiAS-VAS complex) in silicon doped GaAs and explain the electrical behaviour of the implanted and annealed material. 相似文献
20.
Pier Domenico Lamberti Massimo Lanza de Cristoforis 《Mathematical Physics, Analysis and Geometry》2006,9(1):65-94
We consider the Dirichlet eigenvalue problem for the Laplace operator on a variable nonsmooth domain. We extend a result of Lupo and Micheletti concerning the structure of the set of domain perturbations which leave the multiplicity of an eigenvalue unchanged, and we study the set of perturbations which leave a certain eigenvalue unchanged. 相似文献