全文获取类型
收费全文 | 140篇 |
免费 | 5篇 |
专业分类
化学 | 49篇 |
晶体学 | 2篇 |
力学 | 17篇 |
数学 | 13篇 |
物理学 | 64篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 12篇 |
2011年 | 14篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 10篇 |
2007年 | 9篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有145条查询结果,搜索用时 15 毫秒
41.
W. Cheikh-Rouhou L.C. Sampaio B. Bartenlian P. Beauvillain A. Brun J. Ferré P. Georges J.-P. Jamet V. Mathet A. Stupakewicz 《Applied physics. B, Lasers and optics》2002,74(7-8):665-670
The optical and magneto-optical second harmonic reflectivity response of Au/Co/Au/Cu multilayers grown on vicinal Si (111)
substrates has been studied. These azimuthal optical non-linear experiments check the uniaxial character of the crystallinity
of the Au buffer layer and the magnetic behavior of the ultrathin Co films in the metallic multilayer. They clearly show the
strong dependence of the growth parameters and the misorientation of the vicinal surface on the SHG reflectivity signals.
This uniaxial behavior is also correlated to linear MOKE experiments on the magnetic anisotropy with an easy magnetization
axis parallel to the step edges.
Received: 16 October 2001 / Published online: 29 May 2002 相似文献
42.
Sabrina Hochheim Naiara M. F. M. Sampaio Anderson Fraga da Cruz Loretta L. del Mercato Eliana D'Amone Bruno José Gonçalves da Silva Cyro Ketzer Saul Carolina Camargo de Oliveira Izabel Riegel-Vidotti 《Macromolecular bioscience》2023,23(5):2200524
Zein, a corn-derived protein, has a variety of applications ranging from drug delivery to tissue engineering and wound healing. This work aims to develop a biocompatible scaffold for dermal applications based on thermally annealed electrospun propolis-loaded zein nanofibers. Pristine fibers' biocompatibility is determined in vitro. Next, propolis from Melipona quadrifasciata is added to the fibers at different concentrations (5% to 25%), and the scaffolds are studied. The physicochemical properties of zein/propolis precursor dispersions are evaluated and the results are correlated to the fibers' properties. Due to zein's and propolis' very favorable interactions, which are responsible for the increase in the dispersions surface tension, nanometric size ribbon-like fibers ranging from 420 to 575 nm are obtained. The fiber's hydrophobicity is not dependent on propolis concentration and increases with the annealing procedure. Propolis inhibitory concentration (IC50) is determined as 61.78 µg mL−1. When loaded into fibers, propolis is gradually delivered to cells as Balb/3T3 fibroblasts and are able to adhere, grow, and interact with pristine and propolis-loaded fibers, and cytotoxicity is not observed. Therefore, the zein–propolis nanofibers are considered biocompatible and safe. The results are promising and provide prospects for the development of wound-healing nanofiber patches—one of propolis' main applications. 相似文献
43.
Pallavi Pushp Frederico Castelo Ferreira Joaquim M. Sampaio Cabral Mukesh Kumar Gupta 《Polymer Science Series A》2017,59(4):515-523
Polycaprolactone (PCL) is a popular synthetic polymer used in the field of cardiac tissue engineering (CTE) due to its non-toxic degraded by products and low cost manufacturing method. However, hydrophobic nature of this material limits its wide spread application in different cell interaction processes. Therefore, current study aims to chemically modify PCL made random and aligned nanofibers with collagen coating mimicking the oriented matrix of the cardiac cells. Morphological and chemical properties of the electrospun PCL nanofibers were evaluated by SEM, FTIR, XRD and water contact angle measurement. Results indicated that the anisotropic characteristics of aligned nanofibers promoted cell attachment and alignment, which closely match the requirements of native cardiac cells. Thus, aligned nanofibers could be preferred for cardiac tissue regeneration and defects over random nanofibers. 相似文献
44.
Jose Ailton Conceicao Bispo Carlos Francisco Sampaio Bonafe Volnei Brito de Souza João Batista de Almeida e Silva Giovani Brandao Mafra de Carvalho 《Journal of mathematical chemistry》2011,49(9):1976-1995
The principal aim of studies of enzyme-mediated reactions has been to provide comparative and quantitative information on
enzyme-catalyzed reactions under distinct conditions. The classic Michaelis–Menten model (Biochem Zeit 49:333, 1913) for enzyme kinetic has been widely used to determine important parameters involved in enzyme catalysis, particularly the
Michaelis–Menten constant (K
M
) and the maximum velocity of reaction (V
max
). Subsequently, a detailed treatment of the mechanisms of enzyme catalysis was undertaken by Briggs–Haldane (Biochem J 19:338,
1925). These authors proposed the steady-state treatment, since its applicability was constrained to this condition. The present
work describes an extending solution of the Michaelis–Menten model without the need for such a steady-state restriction. We
provide the first analysis of all of the individual reaction constants calculated analytically. Using this approach, it is
possible to accurately predict the results under new experimental conditions and to characterize and optimize industrial processes
in the fields of chemical and food engineering, pharmaceuticals and biotechnology. 相似文献
45.
Leite JF Assreuy AM Mota MR Bringel PH Lacerda RR Gomes Vde M Cajazeiras JB Nascimento KS Pessôa Hde L Gadelha CA Delatorre P Cavada BS Santi-Gadelha T 《Molecules (Basel, Switzerland)》2012,17(3):3277-3290
Lectins are proteins that have the ability to bind specifically and reversibly to carbohydrates and glycoconjugates, without altering the structure of the glycosyl ligand. They are found in organisms such as viruses, plants and humans, and they have been shown to possess important biological activities. The objective of this study was to purify and characterize lectins in the seeds of Clitoria fairchildiana, as well as to verify their biological activities. The results indicated the presence of a lectin (CFAL) in the glutelin acid protein fraction, which agglutinated native rabbit erythrocytes. CFAL was purified by column chromatography ion-exchange, DEAE-Sephacel, which was obtained from a peak of protein retained in the matrix by applying 0.5 M NaCl using the step-wise method. Electrophoretic analysis of this lectin in SDS-PAGE indicated a two band pattern protein molecular mass of approximately 100 and 116 kDa. CFAL proved to be unspecific to all carbohydrates/glycoconjugates in common use for the sugar inhibition test. This lectin showed no significant cytotoxicity to human red blood cells. It was observed that CFAL has anti-inflammatory activity in the paw edema induced by carrageenan model, in which a 64% diminution in edema was observed. Antinociceptive effects were observed for CFAL in the abdominal writhing test (induced by acetic acid), in which increasing doses of the lectin caused reduction in the number of contortions by up to 72%. It was concluded that the purified and characterized lectin from the seeds of Clitoria fairchildiana has anti-inflammatory and antinociceptive activity, and is not cytotoxic to human erythrocytes. 相似文献
46.
Fernanda Irma Remus Hamester Dbora Santos da Silva Ana Paula Magalhes Leboute Carlos Henrique Ares Motta Clarice Sampaio Alho 《Electrophoresis》2019,40(21):2873-2876
Well‐defined estimates of mutation rates in highly polymorphic tetranucleotide STR loci are a prerequisite for human identification in genetics laboratory routines useful for civil and criminal investigations. Studying 15 autosomal STR loci of forensic interest (CSF1PO, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPOX, and vWA), we detected 193 slippage mutations (189 one‐step and four two‐step mutations) in 148 875 parent‐child allelic transfers from 5171 paternity cases with true biological relationship (15 096 individuals; 4754 trios and 417 duos; 9925 meiosis) from the state of São Paulo, a very representative population of Brazil. The overall mutation rate was 1.3 × 10?3 and the highest rates were observed at loci vWA (2.8 × 10?3), FGA and D18S51 (2.7 × 10?3 for both), while loci TH01 and TPOX did not present any mutations. The mean slippage mutation rate of paternal origin (1.8 × 10?3) was six times higher than that observed for maternal origin (0.3 × 10?3). 相似文献
47.
48.
The investigation of K‐shell fluorescence parameters of Zn–Fe alloys with different grain size and microstrain values
下载免费PDF全文
![点击此处可从《X射线光谱测定》网站下载免费的PDF全文](/ch/ext_images/free.gif)
N. Kup Aylikci J.M. Sampaio A. Kahoul V. Aylikci I.H. Karahan M. Guerra J.P. Santos J.P. Marques E. Tiraşoğlu 《X射线光谱测定》2017,46(4):242-251
It is known that zinc alloys with iron group metals have better corrosion resistance than pure zinc. Owing to the corrosion resistance of these alloys, Zn–Fe coatings are widely used in automotive industry and have excellent mechanical performance. In this work, we investigated the relationship between the changes in the measured X‐ray fluorescence parameters (Kβ/Kα, σKα and σKβ) and the changes in the structural parameters such as microstrain or grain size values for Zn–Fe alloys that were prepared with different pH values. To explain these changes, the Kα and KβX‐ray production cross sections, and the Kβ/KαX‐ray intensity ratio values were calculated by three different ways for the elemental forms of Zn and Fe. The structural parameters, such as microstrain and grain size, were also calculated. We expect that the outer shell electronic distribution affects the structural parameters of the produced Zn–Fe alloys, changing the measured Kα and KβX‐ray production cross sections, and the Kβ/KαX‐ray intensity ratio values. We also show that Zn–Fe alloy mi nimum microstrain value corresponds to the maximum changes in KβX‐ray production cross‐section values of Fe and Zn. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
49.
50.
A new finite element formulation designed for both compressible and nearly incompressible viscous flows is presented. The formulation combines conservative and non‐conservative dependent variables, namely, the mass–velocity (density * velocity), internal energy and pressure. The central feature of the method is the derivation of a discretized equation for pressure, where pressure contributions arising from the mass, momentum and energy balances are taken implicitly in the time discretization. The method is applied to the analysis of laminar flows governed by the Navier–Stokes equations in both compressible and nearly incompressible regimes. Numerical examples, covering a wide range of Mach number, demonstrate the robustness and versatility of the new method. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献