全文获取类型
收费全文 | 102篇 |
免费 | 3篇 |
专业分类
化学 | 61篇 |
晶体学 | 3篇 |
数学 | 3篇 |
物理学 | 22篇 |
无线电 | 16篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 4篇 |
2012年 | 8篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2001年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1986年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1960年 | 1篇 |
排序方式: 共有105条查询结果,搜索用时 15 毫秒
21.
Todor G. Deligeorgiev Stefka Kaloyanova Aleksey Vasilev Juan J. Vaquero 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2292-2302
An improved green procedure for the synthesis of 2-aryl- and 2-hetarylbenzothiazoles by condensation of equivalent amounts of 2,2′-diaminodiphenyldisulfides or 2-aminothiophenols and various aromatic aldehydes in PEG 200/400 under microwave irradiation has been developed. This method allows the synthesis of 2-arylbenzothiazoles in high yields and with high purity regardless of the state of the starting compounds (liquid or solid) or the nature of the substituents in the aromatic ring. 相似文献
22.
The growing demand for titanium-based implants and the subsequent rise in implant-associated infections necessitate novel developments in anti-infective technologies. Recent research has drawn inspiration from nature to solve this problem. The nanoscale topography observed on cicada and dragonfly wings serves as a blueprint for synthetic analogs which seek to kill bacteria on contact through mechanical forces. This type of interaction has been dubbed the mechano-bactericidal effect. Various techniques have been utilized to mimic and improve upon these natural bactericidal surfaces. Alkaline hydrothermal etching is a simple and cost-effective technique to fabricate nanoscale protrusions on titanium and its alloys. This review aims to consolidate the current knowledge surrounding how fabrication parameters lead to varying surface topographies on titanium substrates, and subsequently, how surface topography and bacterial characteristics affect bactericidal activity. The bactericidal mechanism of hydrothermally etched titanium is inferred from comparisons with similar mechano-bactericidal biomaterials. The hostility of hydrothermally etched titanium toward bacteria is discussed in contrast to the observed host cell compatibility. Last, suggestions are made for the standardization of terminology in this emerging field. 相似文献
23.
Rahul M. Visalakshan Alex A. Cavallaro Melanie N. MacGregor Emma P. Lawrence Kaloian Koynov John D. Hayball Krasimir Vasilev 《Advanced functional materials》2019,29(14)
Surface nanotopograpy has been recognized as an important regulator of cellular responses including those of immune cells, the latter being of particular importance for implantable materials since these can determine biomaterial fate. In this paper, evidence is provided that the scale of surface nanotopography modulates the conformation of attached serum proteins, which in turn controls immune cell adhesion and activation. Model surfaces of tailored nanotopography of heights of 16, 38, and 68 nm are created by covalent immobilization of gold nanoparticles to an oxazoline‐rich plasma polymer film. This strategy not only produces surfaces of tailored nanofeature density but allows control of the outermost surface chemistry. Circular dichroism spectroscopy and Mac‐1 positive THP‐1 monocytes studies demonstrate distinct protein unfolding patterns, which upregulate or downregulate the expression of proinflammatory cytokines and cells attachment. The findings presented in this paper shed light on the missing relationship between surface nanotopography, protein unfolding, and the immune response. On the other hand, this work demonstrates the possibility to use specifically tailored surface nanotoporaphy scales to modulate and achieve desired immune responses. 相似文献
24.
Mekenyan O Dimitrov S Dimitrova N Dimitrova G Pavlov T Chankov G Kotov S Vasilev K Vasilev R 《SAR and QSAR in environmental research》2006,17(1):107-120
The role of metabolism in prioritising chemicals according to their potential adverse health effects is extremely important given the fact that innocuous parents can be transformed into toxic metabolites. Our recent efforts in simulating metabolic activation of chemicals are reviewed in this work. The application of metabolic simulators to predict biodegradation (microbial degradation pathways), bioaccumulation (fish liver metabolism), skin sensitisation (skin metabolism), mutagenicity (rat liver S-9 metabolism) are discussed. The ability of OASIS approach to predict metabolism (toxicokinetics) and toxicity (toxicodynamics) of chemicals resulting from their metabolic activation in a single modelling platform is an important advantage of the method. It allows prioritisation of chemicals due to predicted toxicity of their metabolites. 相似文献
25.
V.A. Gritsenko S.S. Nekrashevich V.V. Vasilev A.V. Shaposhnikov 《Microelectronic Engineering》2009,86(7-9):1866-1869
From experiments on photoluminescence in Si3N4 the polaron energy of 1.4 eV was determined. This value is in agreement with the energy of thermal ionization determined from electron and hole transport. Quantum-chemical simulation showed that Si–Si bond is able to capture holes and electrons in Si3N4. 相似文献
26.
27.
28.
29.
Vasilev K Stefani FD Jacobsen V Knoll W Kreiter M 《The Journal of chemical physics》2004,120(14):6701-6704
The photobleaching of chromophores in front of a metal film is measured by recording the emitted fluorescence intensity from an ensemble of chromophores as a function of time. A strong dependence of the photostability on the distance from the metal surface is found. The experimental data are well described in a classical electromagnetic model with the additional assumption that photobleaching occurs at a constant rate from the excited state. The metal interface influences the photostability of the chromophores in two ways, first by altering the excitation rate by local enhancement of the electromagnetic field and second by altering the electromagnetic decay rate. 相似文献
30.
Stoyanka Christoskova Maria Stoyanova Dragomir Vasilev 《Monatshefte für Chemie / Chemical Monthly》2006,9(6):1043-1051
The effect of the synthesis conditions of individual and modified with Mn Ni- and Co-oxide systems on the content and the
mobility of their active oxygen has been studied by means of chemical and IR spectral analyses. The results obtained show
that the main part of the active oxygen in Ni-oxide system is located on the catalyst’s surface (Os
* is approximately 73% of the total active oxygen), while Co-oxide system is characterized by much lower surface active oxygen
content. Ni- and Co-oxide systems modified with Mn have comparatively higher active oxygen content as compared to the individual
ones. Data of the IR spectral analysis reveal that Mn, as a modifying component, affects the mobility of the active oxygen,
the latter contributing to the activity of oxide systems in oxidation processes. The high content of loosely bonded active
oxygen formed during the synthesis determines a high catalytic activity of the studied samples in reactions of complete oxidation
in the low temperature region. 相似文献