全文获取类型
收费全文 | 135篇 |
免费 | 5篇 |
专业分类
化学 | 100篇 |
晶体学 | 2篇 |
数学 | 17篇 |
物理学 | 21篇 |
出版年
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 5篇 |
2013年 | 19篇 |
2012年 | 14篇 |
2011年 | 15篇 |
2010年 | 14篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 3篇 |
1969年 | 1篇 |
排序方式: 共有140条查询结果,搜索用时 31 毫秒
121.
Iuliana Spiridon Ramona Gabriela Ursu Irene Alexandra Cianga Spiridon 《International Journal of Polymer Analysis and Characterization》2015,20(8):681-692
The interest in antimicrobial packaging materials based on polylactic acid (PLA) polymers has increased due to the need to improve food safety and environment quality and also to find alternatives to synthetic polymers made from petrochemicals. PLA films by addition of different fillers (grape wastes and celery fibers) were obtained. The mechanical, thermal, surface, and antimicrobial properties of the films were evaluated. The incorporation of inexpensive fillers into the PLA matrix could reduce costs and the studied formulations offer approaches to realize composites with high performances and antimicrobial response, suitable for film food-active packaging materials, especially by use of grape wastes. 相似文献
122.
Nicolae Dan Tesloianu Lucian Dobreci Vlad Ghizdovat Andrei Zala Adrian Valentin Cotirlet Alina Gavrilut Maricel Agop Decebal Vasincu Igor Nedelciuc Cristina Marcela Rusu Irina Iuliana Costache 《Entropy (Basel, Switzerland)》2021,23(4)
By assimilating biological systems, both structural and functional, into multifractal objects, their behavior can be described in the framework of the scale relativity theory, in any of its forms (standard form in Nottale’s sense and/or the form of the multifractal theory of motion). By operating in the context of the multifractal theory of motion, based on multifractalization through non-Markovian stochastic processes, the main results of Nottale’s theory can be generalized (specific momentum conservation laws, both at differentiable and non-differentiable resolution scales, specific momentum conservation law associated with the differentiable–non-differentiable scale transition, etc.). In such a context, all results are explicated through analyzing biological processes, such as acute arterial occlusions as scale transitions. Thus, we show through a biophysical multifractal model that the blocking of the lumen of a healthy artery can happen as a result of the “stopping effect” associated with the differentiable-non-differentiable scale transition. We consider that blood entities move on continuous but non-differentiable (multifractal) curves. We determine the biophysical parameters that characterize the blood flow as a Bingham-type rheological fluid through a normal arterial structure assimilated with a horizontal “pipe” with circular symmetry. Our model has been validated based on experimental clinical data. 相似文献
123.
Mihaela Avadanei Mioara Drobota Iuliana Stoica Elena Rusu Virgil Barboiu 《Journal of polymer science. Part A, Polymer chemistry》2010,48(23):5456-5467
Surface of biaxially oriented poly(ethylene terephthalate) films was chemically modified by exposure to ethylenediamine (EDA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA) for different treatment times. Variable angle attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopy was used in conjunction with weight loss measurements, scanning electron microscopy (SEM), and atomic force microscopy to establish the surface modification and to draw the depth profile of the newly created species, with emphasis on amide group. A clear differentiation was found between the effects of the three amines studied: EDA produces the highest amidation degree but, because of its deep penetration into the film, leads to delamination of rather thick layers, TETA reacts at and near surface and develops surface cracks without delamination, and TEPA is the mildest reactant, generating amide groups on the surface without visible deterioration of the sample. It was proved that the amide II absorption band became weaker with increasing analyzed depth, with a pronounced heterogeneity near the surface. SEM micrographs showed the development of cracks onto the surface at longer aminolysis time, which allowed a better understanding of ATR‐FTIR observations. Assuming an exponential decay for the depth profile spectrally obtained, the surface concentration of amide groups and the decay constant were determined for the amines and reaction times used. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
124.
Variously substituted novel dihydropyridoazepinones have been prepared by an intermolecular radical addition followed by a radical cyclisation on a pyridine ring. The latter process involved the use of a combination of two different peroxides, an experimental contrivance resulting from a careful product analysis and a better understanding of the cyclisation step. 相似文献
125.
This study aims to evidence the influence of polyelectrolytes structure and the number of double layers on the properties
of some new nanostructured architectures formed by layer-by-layer self-assembly of complementary weak polyelectrolytes on
planar surfaces. For this purpose, we used chitosan and poly(allylamine hydrochloride) as polycations, and poly(acrylic acid)
and poly(2-acrylamido-2-methylpropanesulfonic acid–co-acrylic acid) as polyanions. To get a direct image on the polyelectrolyte
multilayers formation and properties, gravimetry, infrared spectroscopy, and atomic force microscopy have been used. The capacity
of the polyions to overcompensate the complementary polyions charges, and thus to influence the swelling degree in water of
thin films, was strongly influenced by the chain structure and flexibility. A special attention was paid to the responsiveness
of the new composite materials to the pH of the swelling environment. 相似文献
126.
A method is described whereby elastomer O-ring performance can be evaluated by compression stress relaxation in a simulated gas turbine lubrication system. The O-ring retained sealing force is measured in real-time during high temperature ageing and during transients to lower temperatures, thus simulating the temperature regimes experienced in an operational gas turbine. In addition to this, the O-rings are exposed to a flow of realistically aged turbine lubricant, producing a realistic level of chemical degradation during testing. The results from this work have demonstrated significant differences between elastomer behaviour due to O-ring material and also due to the temperature regimes subjected to during compression stress relaxation. Taken as a whole, this work represents a considerable improvement on current elastomer O-ring test methods as applied to gas turbine lubricant system seals. 相似文献
127.
Adrian Carabineanu Adrian Dinu Iuliana Oprea 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1995,46(6):971-981
A boundary element method is developed in order to investigate the flow of viscous, incompressible, electrically conducting fluids in cylindrical ducts having arbitrary cross-sections. The numerical results obtained for the circular duct with insulating wall are very close to the results obtained by means of analytical formulas. 相似文献
128.
Neutron activation analysis combined with chemical preconcentration of the elements in water samples can give a high sensitivity in the determination of concentrations for In-EDTA, I– and Br– used as activable tracers in hydrological studies. The authors have developed an improved method of analysis which is sensitive, selective and applicable to a wide range of underground and surface water samples including those having a high concentration of manganese ions. 相似文献
129.
A. Lucaciu L. Staicu S. Spiridon N. Scintee D. Arizan 《Journal of Radioanalytical and Nuclear Chemistry》1997,216(1):29-31
A method was developed for the determination of element concentrations in structured water samples (water with high oligoelements content). Sixteen elements (As, Br, Ca, Ce, Co, Cr, Eu, Fe, K, La, Lu, Na, Sb, Sc, Sm, Zn) were determined in 4 structured water samples and one taken from the water tap. The samples were preconcentrated evaporating 1 1 at atmospheric pressure and obtaining 100–500 mg of dry residue. Measurement accuracy by -spectroscopy was 3–30% and it can be improved by increasing the measurement time. The method allows simultaneous multielement analysis of various water sources and may successfully be used in environmental pollution control. 相似文献
130.
Prof. Dr. C. Drăgulescu E. Petrovici Iuliana Lupu 《Monatshefte für Chemie / Chemical Monthly》1974,105(6):1170-1175
Hexachloroantimonates with nitroderivatives as ligands on the cations are formed in a double complexation reaction of a mono-valent metal chloride (LiCl, NaCl, KCl, CuCl) with SbCl5, and a nitroderivativeL (nitromethane, nitrobenzene, α-nitronaphthalene). Solid complexes of the typeML(SbCl6) andML 2(SbCl6) were isolated. Synthesis, analytical results andi.r. spectra are discussed. 相似文献