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排序方式: 共有272条查询结果,搜索用时 62 毫秒
41.
Vysakh A. Bharathan Govind K. Raj Pattayil A. Joy Chathakudath P. Vinod 《Particle & Particle Systems Characterization》2014,31(2):236-244
Core–shell bimetallic Au@Ni nanoparticles, with gold cores and thin nickel shells with overall size less than 10 nm, are synthesized and stabilized in pure cubic (fcc) and hexagonal (hcp) phase. Due to their unique crystal, electronic, and geometric structure, they show interesting magnetic and chemical properties. The Au@Nifcc is magnetic, whereas Au@Nihcp is non‐magnetic. Both the bimetallic nanostructures are stable to surface oxidation until 150 °C and show excellent catalytic activity for p‐nitrophenol reduction reaction. 相似文献
42.
Dr. Govind V. Kaigala Robert D. Lovchik Dr. Emmanuel Delamarche 《Angewandte Chemie (International ed. in English)》2012,51(45):11224-11240
Local interactions between (bio)chemicals and biological interfaces play an important role in fields ranging from surface patterning to cell toxicology. These interactions can be studied using microfluidic systems that operate in the “open space”, that is, without the need for the sealed channels and chambers commonly used in microfluidics. This emerging class of techniques localizes chemical reactions on biological interfaces or specimens without imposing significant “constraints” on samples, such as encapsulation, pre‐processing steps, or the need for scaffolds. They therefore provide new opportunities for handling, analyzing, and interacting with biological samples. The motivation for performing localized chemistry is discussed, as are the requirements imposed on localization techniques. Three classes of microfluidic systems operating in the open space, based on microelectrochemistry, multiphase transport, and hydrodynamic flow confinement of liquids are presented. 相似文献
43.
Govind Menon 《数学物理学报(B辑英文版)》2012,(1):281-294
This article is a short introduction to the surprising appearance of Burgers equation in some basic probabilistic models. 相似文献
44.
Har Mohindra Chawla Geeta Hundal S. Kumar Parminder Singh 《Journal of inclusion phenomena and macrocyclic chemistry》2012,72(3-4):323-330
Calix[4]arenes possessing electron-donating groups (OH and OR) at the lower rim when reacted with tosylated polyethers under basic conditions give the corresponding 1,3-disubstituted calix[4]arene-crown ethers 2a–2h, in good yields. The binding properties of the synthesized 1,3-bridged calix[4]arene-crown ethers for alkali metal cations have been investigated by atomic emission spectrometric analysis. It has been observed that recognition of sodium and potassium varies with the size of the polyether chain as well as the substituents on the free phenolics of the calix[4]arene-crown ether. The potassium/sodium selectivity seems to be governed primarily by the size of the crown ring, relative hydrophobicity and cation-π interaction capability to give efficiency order as 2a, 2d?>?2?h?>?2c, 2e?>?2b, 2f?>?2?g. 相似文献
45.
Govind K. Menon 《General Relativity and Gravitation》2001,33(4):631-640
The basic formalism for conformal fluctuations of the gravitational field is presented. After developing a master propagator for the interior Schwarzschild solution, the time development of the gravitational wave function is considered. The effect of the two classical singularities (resp. pseudo-singularities) of the Schwarzschild solution on the quantum wave function for the gravitational field is studied using a wave function initially localized on the classical solution. While the true singularity at r = 0 imparts consequences on the wave function that cannot be ignored, the pseudo-singularity at the event horizon does not seem to cause any divergences on the interior fluctuations of the Schwarzschild solution. 相似文献
46.
We study limiting behavior of rescaled size distributions that evolve by Smoluchowski's rate equations for coagulation, with rate kernel K=2, x+y or xy. We find that the dynamics naturally extend to probability distributions on the half-line with zero and infinity appended, representing populations of clusters of zero and infinite size. The “scaling attractor” (set of subsequential limits) is compact and has a Levy-Khintchine-type representation that linearizes the dynamics and allows one to establish several signatures of chaos. In particular, for any given solution trajectory, there is a dense family of initial distributions (with the same initial tail) that yield scaling trajectories that shadow the given one for all time. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
47.
48.
We establish necessary and sufficient conditions for the shock statistics to approach self-similar form in Burgers turbulence
with Lévy process initial data. The proof relies upon an elegant closure theorem of Bertoin and Carraro and Duchon that reduces
the study of shock statistics to Smoluchowski’s coagulation equation with additive kernel, and upon our previous characterization
of the domains of attraction of self-similar solutions for this equation. 相似文献
49.
50.
We consider the approach to self‐similarity (or dynamical scaling) in Smoluchowski's equations of coagulation for the solvable kernels K(x, y) = 2, x + y and xy. In addition to the known self‐similar solutions with exponential tails, there are one‐parameter families of solutions with algebraic decay, whose form is related to heavy‐tailed distributions well‐known in probability theory. For K = 2 the size distribution is Mittag‐Leffler, and for K = x + y and K = xy it is a power‐law rescaling of a maximally skewed α‐stable Lévy distribution. We characterize completely the domains of attraction of all self‐similar solutions under weak convergence of measures. Our results are analogous to the classical characterization of stable distributions in probability theory. The proofs are simple, relying on the Laplace transform and a fundamental rigidity lemma for scaling limits. © 2003 Wiley Periodicals, Inc. 相似文献