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41.
The behavior of the random graph G(n,p) around the critical probability pc = is well understood. When p = (1 + O(n1/3))pc the components are roughly of size n2/3 and converge, when scaled by n?2/3, to excursion lengths of a Brownian motion with parabolic drift. In particular, in this regime, they are not concentrated. When p = (1 ‐ ?(n))pc with ?(n)n1/3 →∞ (the subcritical regime) the largest component is concentrated around 2??2 log(?3n). When p = (1 + ?(n))pc with ?(n)n1/3 →∞ (the supercritical regime), the largest component is concentrated around 2?n and a duality principle holds: other component sizes are distributed as in the subcritical regime. Itai Benjamini asked whether the same phenomenon occurs in a random d‐regular graph. Some results in this direction were obtained by (Pittel, Ann probab 36 (2008) 1359–1389). In this work, we give a complete affirmative answer, showing that the same limiting behavior (with suitable d dependent factors in the non‐critical regimes) extends to random d‐regular graphs. © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2010 相似文献
42.
The weighted matroid parity problems for the matching matroid and gammoids are among the very few cases for which the weighted matroid parity problem is polynomial time solvable. In this work we extend these problems to a general revenue function for each pair, and show that the resulting problem is still solvable in polynomial time via a standard weighted matching algorithm. We show that in many other directions, extending our results further is impossible (unless P = NP). One consequence of the new polynomial time algorithm is that it demonstrates, for the first time, that a prize-collecting assignment problem with “pair restriction” is solved in polynomial time. The prize collecting assignment problem is a relaxation of the prize-collecting traveling salesman problem which requires, for any prescribed pair of nodes, either both nodes of the pair are matched or none of them are. It is shown that the prize collecting assignment problem is equivalent to the prize collecting cycle cover problem which is hence solvable in polynomial time as well. 相似文献
43.
44.
J. Lapid M. Miinster S. Farhi M. Eini L. Lalouche 《Journal of Radioanalytical and Nuclear Chemistry》1984,86(5):321-326
A rapid analytical method, applicable for the selective separation and determination of90Sr and89Sr in river water, is described. Strontium is extracted from the water sample at pH 10.5 by TTA/TOPO in cyclohexane in the presence of Tiron as masking agent for interfering ß-emitters. Radiostrontium is measured by liquid scintillation after back-extraction into 1N nitric acid. The distribution coefficient of strontium is over 400 and the separation factors from other radionuclides are higher than 5.0×103. 相似文献
45.
R. Farhi M. El Marssi A. Simon J. Ravez 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,9(4):599-604
Dielectric and Raman scattering experiments were performed on various ceramics with composition Ba(Ti1-xZrx)O3. Such lead-free, environmental-friendly materials were shown, from dielectric measurements, to exhibit behaviours extending
from conventional to relaxor ferroelectrics on increasing the zirconium concentration. The evolution of the Raman spectra
was studied as a function of temperature for various compositions, and the spectroscopic signature of the corresponding phases
was determined. In the relaxor state, the variation of the integrated intensity of the Raman lines with temperature showed
a plateau at low temperature. This anomaly was also detected as a peak in depolarization current measurements, and attributed
to ergodicity breaking which characterizes usual relaxor systems. Raman results hint at locally rhombohedral polar nanoregions
resulting from the random fields associated with Zr ions.
Received 25 September 1998 相似文献
46.
47.
Bakir Farhi 《Comptes Rendus Mathematique》2005,341(8):469-474
We present here a method which allows to derive a nontrivial lower bounds for the least common multiple of some finite sequences of integers. We obtain efficient lower bounds (which in a way are optimal) for the arithmetical progressions and lower bounds less efficient (but nontrivial) for some class of quadratic sequences.In the last part of this Note, we study the integer (). We show that it has a divisor simple in its dependence on n and k, and a multiple also simple in its dependence on n. In addition, we prove that both equalities: and hold for infinitely many pairs . To cite this article: B. Farhi, C. R. Acad. Sci. Paris, Ser. I 341 (2005). 相似文献
48.
The thermodynamic equilibrium Sn(l) + O2(g) = SnO2(s) has been studied between 773 and 1380 K by e.m.f. measurements on cells involving a solid electrolyte, of the type: 相似文献
49.
We report neutron-scattering measurements of the phonons in bcc solid 4He. In general, only three acoustic phonon branches should exist in a monatomic cubic crystal. In addition to these phonon branches, we found a new "opticlike" mode along the [110] direction. One possible interpretation of this new mode is in terms of localized excitations unique to a quantum solid. 相似文献
50.
Self‐Assembled Cyclic d,l‐α‐Peptides as Generic Conformational Inhibitors of the α‐Synuclein Aggregation and Toxicity: In Vitro and Mechanistic Studies
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Dr. Marina Chemerovski‐Glikman Eva Rozentur‐Shkop Dr. Michal Richman Dr. Asaf Grupi Asaf Getler Prof. Haim Y. Cohen Dr. Hadassa Shaked Cecilia Wallin Dr. Sebastian K. T. S. Wärmländer Prof. Elisha Haas Prof. Astrid Gräslund Prof. Jordan H. Chill Prof. Shai Rahimipour 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14236-14246
Many peptides and proteins with large sequences and structural differences self‐assemble into disease‐causing amyloids that share very similar biochemical and biophysical characteristics, which may contribute to their cross‐interaction. Here, we demonstrate how the self‐assembled, cyclic d,l ‐α‐peptide CP‐2 , which has similar structural and functional properties to those of amyloids, acts as a generic inhibitor of the Parkinson′s disease associated α‐synuclein (α‐syn) aggregation to toxic oligomers by an ?off‐pathway“ mechanism. We show that CP‐2 interacts with the N‐terminal and the non‐amyloid‐β component region of α‐syn, which are responsible for α‐syn′s membrane intercalation and self‐assembly, thus changing the overall conformation of α‐syn. CP‐2 also remodels α‐syn fibrils to nontoxic amorphous species and permeates cells through endosomes/lysosomes to reduce the accumulation and toxicity of intracellular α‐syn in neuronal cells overexpressing α‐syn. Our studies suggest that targeting the common structural conformation of amyloids may be a promising approach for developing new therapeutics for amyloidogenic diseases. 相似文献