全文获取类型
收费全文 | 166篇 |
免费 | 5篇 |
专业分类
化学 | 115篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 12篇 |
物理学 | 40篇 |
出版年
2023年 | 1篇 |
2022年 | 9篇 |
2021年 | 4篇 |
2020年 | 11篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 7篇 |
2012年 | 14篇 |
2011年 | 15篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 11篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 1篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1970年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有171条查询结果,搜索用时 31 毫秒
101.
102.
Olivier Gautreau Lina Gunawan M.P. Singh Gianluigi A. Botton 《Journal of magnetism and magnetic materials》2009,321(11):1799-1802
The multiferroic behavior of epitaxial γ-Fe2O3-BiFeO3 (composite)/Bi3.25La0.75Ti3O12 bi-layered heterostructures grown on SrRuO3/SrTiO3 (1 1 1) substrates has been studied using piezoresponse force microscopy, magnetic force microscopy and magnetometry. The ferroelectric domain structure is ascribed to the BiFeO3 phase while the magnetism originates in the γ-Fe2O3 phase of the composite layer. Our studies demonstrate the presence and switching of magnetic and ferroelectric domains within the same area of the sample. This confirms the presence of multiferroic behavior at the nanoscale in our γ-Fe2O3-BiFeO3 nanocomposite thin films. 相似文献
103.
Leonid A. Bunimovich Gianluigi Del Magno 《Communications in Mathematical Physics》2009,288(2):699-713
We study a class of planar billiards having the remarkable property that their phase space consists up to a set of zero measure
of two invariant sets formed by orbits moving in opposite directions. The tables of these billiards are tubular neighborhoods
of differentiable Jordan curves that are unions of finitely many segments and arcs of circles. We prove that under proper
conditions on the segments and the arcs, the billiards considered have non-zero Lyapunov exponents almost everywhere. These
results are then extended to a similar class of 3-dimensional billiards. Interestingly, we find that for some track billiards,
the mechanism generating hyperbolicity is not the defocusing one, which requires every infinitesimal beam of parallel rays
to defocus after every reflection off of the focusing boundary. 相似文献
104.
This work focuses on the approximation of parametric steady Navier–Stokes equations by the reduced basis method. For a particular instance of the parameters under consideration, we are able to solve the underlying partial differential equations, compute an output, and give sharp error bounds. The computations are split into an offline part, where the values of the parameters are not yet identified, but only given within a range of interest, and an online part, where the problem is solved for an instance of the parameters. The offline part is expensive and is used to build a reduced basis and prepare all the ingredients – mainly matrix–vector and scalar products, but also eigenvalue computations – necessary for the online part, which is fast. 相似文献
105.
106.
107.
Hypergeometric-Gaussian modes 总被引:1,自引:0,他引:1
We studied a novel family of paraxial laser beams forming an overcomplete yet nonorthogonal set of modes. These modes have a singular phase profile and are eigenfunctions of the photon orbital angular momentum. The intensity profile is characterized by a single brilliant ring with the singularity at its center, where the field amplitude vanishes. The complex amplitude is proportional to the degenerate (confluent) hypergeometric function, and therefore we term such beams hypergeometric-Gaussian (HyGG) modes. Unlike the recently introduced hypergeometric modes [Opt. Lett. 32, 742 (2007)], the HyGG modes carry a finite power and have been generated in this work with a liquid-crystal spatial light modulator. We briefly consider some subfamilies of the HyGG modes as the modified Bessel Gaussian modes, the modified exponential Gaussian modes, and the modified Laguerre-Gaussian modes. 相似文献
108.
In the context of naturally occurring nitrogen heterocycles, nicotine is a chiral alkaloid present in tobacco plants, which can target and stimulate nicotinic acetylcholine receptors (nAChRs), a class of ligand-gated ion channels commonly located throughout the human brain. Due to its well-known toxicity for humans, there is considerable interest in the development of synthetic analogues; in particular, conformationally restricted analogues of nicotine have emerged as promising drug molecules for selective nAChR-targeting ligands. In the present mini-review, we will describe the synthesis of the conformationally restricted analogues of nicotine involving one or more catalytic processes. In particular, we will follow a systematic approach as a function of the heteroarene structure, considering: (a) 2,3-annulated tricyclic derivatives; (b) 3,4-annulated tricyclic derivatives; (c) tetracyclic derivatives; and (d) other polycyclic derivatives. For each of them we will also consider, when carried out, biological studies on their activity for specific nAChR subunits. 相似文献
109.
Dafne Ruggiero Stefania Terracciano Gianluigi Lauro Michela Pecoraro Silvia Franceschelli Giuseppe Bifulco Ines Bruno 《Molecules (Basel, Switzerland)》2022,27(3)
The multidomain BAG3 protein is a member of the BAG (Bcl-2-associated athanogene) family of co-chaperones, involved in a wide range of protein–protein interactions crucial for many key cellular pathways, including autophagy, cytoskeletal dynamics, and apoptosis. Basal expression of BAG3 is elevated in several tumor cell lines, where it promotes cell survival signaling and apoptosis resistance through the interaction with many protein partners. In addition, its role as a key player of several hallmarks of cancer, such as metastasis, angiogenesis, autophagy activation, and apoptosis inhibition, has been established. Due to its involvement in malignant transformation, BAG3 has emerged as a potential and effective biological target to control multiple cancer-related signaling pathways. Recently, by using a multidisciplinary approach we reported the first synthetic BAG3 modulator interfering with its BAG domain (BD), based on a 2,4-thiazolidinedione scaffold and endowed with significant anti-proliferative activity. Here, a further in silico-driven selection of a 2,4-thiazolidinedione-based compound was performed. Thanks to a straightforward synthesis, relevant binding affinity for the BAG3BD domain, and attractive biological activities, this novel generation of compounds is of great interest for the development of further BAG3 binders, as well as for the elucidation of the biological roles of this protein in tumors. Specifically, we found compound 6 as a new BAG3 modulator with a relevant antiproliferative effect on two different cancer cell lines (IC50: A375 = 19.36 μM; HeLa = 18.67 μM). 相似文献
110.
Gianluigi De Falco Ingrid El Helou Pedro M. de Oliveira Mariano Sirignano Ruoyang Yuan Andrea D'Anna Epaminondas Mastorakos 《Proceedings of the Combustion Institute》2021,38(2):2691-2699
There is a need to better understand particle size distributions (PSDs) from turbulent flames from a theoretical, practical and even regulatory perspective. Experiments were conducted on a sooting turbulent non-premixed swirled ethylene flame with secondary (dilution) air injection to investigate exhaust and in-burner PSDs measured with a Scanning Mobility Particle Sizer (SMPS) and soot volume fractions (fv) using extinction measurements. The focus was to understand the effect of systematically changing the amount and location of dilution air injection on the PSDs and fv inside the burner and at the exhaust. The PSDs were also compared with planar Laser Induced Incandescence (LII) calibrated against the average fv. LII provides some supplemental information on the relative soot amounts and spatial distribution among the various flow conditions that helps interpret the results. For the flame with no air dilution, fv drops gradually along the centreline of the burner towards the exhaust and the PSD shows a shift from larger particles to smaller. However, with dilution air fv reduces sharply where the dilution jets meet the burner axis. Downstream of the dilution jets fv reduces gradually and the PSDs remain unchanged until the exhaust. At the exhaust, the flame with no air dilution shows significantly more particles with an fv one to two orders of magnitude greater compared to the Cases with dilution. This dataset provides insights into soot spatial and particle size distributions within turbulent flames of relevance to gas turbine combustion with differing dilution parameters and the effect dilution has on the particle size. Additionally, this work measures fv using both ex situ and in situ techniques, and highlights the difficulties associated with comparing results across the two. The results are useful for validating advanced models for turbulent combustion. 相似文献