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351.
V. Karagkiozaki P.G. KaragiannidisM. Gioti P. KavatzikidouD. Georgiou E. GeorgarakiS. Logothetidis 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
An exciting direction in nanomedicine would be to analyze how living cells respond to conducting polymers. Their application for tissue regeneration may advance the performance of drug eluting stents by addressing the delayed stent re-endothelialization and late stent thrombosis.Methods
The suitability of poly (3, 4-ethylenedioxythiophene) (PEDOT) thin films for stents to promote cell adhesion and proliferation is tested in correlation with doping and physicochemical properties. PEDOT doped either with poly (styrenesulfonate) (PSS) or tosylate anion (TOS) was used for films' fabrication by spin coating and vapor phase polymerization respectively. PEGylation of PEDOT: TOS for reduced immunogenicity and biofunctionalization of PEDOT: PSS with RGD peptides for induced cell proliferation was further applied. Atomic Force Microscopy and Spectroscopic Ellipsometry were implemented for nanotopographical, structural, optical and conductivity measurements in parallel with wettability and protein adsorption studies. Direct and extract testing of cell viability and proliferation of L929 fibroblasts on PEDOT samples by MTT assay in line with SEM studies follow.Results
All PEDOT thin films are cytocompatible and promote human serum albumin adsorption. PEDOT:TOS films were found superior regarding cell adhesion as compared to controls. Their nanotopography and hydrophilicity are significant factors that influence cytocompatibility. PEGylation of PEDOT:TOS increases their conductivity and hydrophilicity with similar results on cell viability with bare PEDOT:TOS. The biofunctionalized PEDOT:PSS thin films show enhanced cell proliferation.Conclusions
The application of PEDOT polymers has evolved as a new perspective to advance stents.General significance
In this work, nanomedicine involving nanotools and novel nanomaterials merges with bioelectronics to stimulate tissue regeneration for cardiovascular implants. This article is part of a Special Issue entitled Organic Bioelectronics — Novel Applications in Biomedicine. 相似文献352.
Georgia Thodi Kleopatra H. Schulpis Elina Molou Vassiliki Georgiou Yannis L. Loukas Yannis Dotsikas Konstantinos Papadopoulos Sofia Biti 《Gene》2013
Biotinidase deficiency (BTD) is an inherited disorder with severe clinical manifestations if not treated early. 63,119 neonates were tested for BTD according to a 3-step protocol. Biotinidase activity was initially estimated through standard colorimetric method on dried blood spots, then the suspected samples were subjected to molecular analysis of the BT gene and determination of BT activity in serum through an HPLC method. 14 infants with partial BTD (incidence 1:4508) were detected. Nine of them were homozygotes (D444H/D444H), and 4 compound heterozygotes carrying D444H combined with Q456H, T532M, C186Y and R157H, respectively. All were asymptomatic and supplemented with 10 mg biotin. Although the number of screened neonates is rather small, it may be suggested that the incidence of the partial BTD infants is the highest ever reported. Detection of BTD should be added to the Greek national neonatal screening program. 相似文献
353.
Cristina Castanha Biao Zhu Caitlin E. Hicks Pries Katerina Georgiou Margaret S. Torn 《Biogeochemistry》2018,137(1-2):267-279
The breakdown and decomposition of plant inputs are critical for nutrient cycling, soil development, and climate-ecosystem feedbacks, but uncertainties persist in how the rates and products of litter decomposition are affected by soil temperature, rhizosphere, and depth of input. We investigated the effects of soil warming (+ 4 °C), rhizosphere, and depth of litter placement on the decomposition of Avena fatua (wild oat grass) root litter in a Mediterranean grassland ecosystem. Field lysimeters were subjected to three environmental treatments (heating, control, and plant removal) and three 13C-labeled root litter addition treatments (to A horizon, to B horizon, and no-addition disturbance control) for each of two harvest time points. We buried root litter in February 2014 and measured loss of 13C in CO2 from the soil surface and in leachate as dissolved organic carbon (DOC) over two growing seasons. At the end of each growing season we recovered the 13C remaining in the soil. Loss of root litter C occurred almost entirely via heterotrophic respiration, with an estimated < 2% lost as DOC during the initial decay period. The added roots were broken down and incorporated into bulk soil material very quickly; only ~ 30% of added root was visible after 6 months. In the first growing season, decomposition occurred faster in the B than in the A horizon, the latter having greater moisture limitation. Subsequently, there was almost no further decomposition in the B horizon. After two growing seasons, less than 20% of the added root litter C remained in the A or B horizons of all environmental treatments. Heating did not stimulate decomposition, likely because it exacerbated the moisture limitation. However, while plots without plants dried down more slowly than plots with plants, their decomposition rate was not significantly greater, possibly due to the lack of rhizosphere processes such as priming. We conclude that in this Mediterranean grassland ecosystem, soil moisture, which is affected by season, depth, heating, and rhizosphere, plays a dominant role in mediating the effect of those factors on root litter decomposition, which after two seasons did not differ by depth or by treatment. 相似文献
354.
Katerina Apostolopoulou Dimitris Konstantinou Rodoula Alataki Ioannis Papapostolou Dimitrios Zisimopoulos Electra Kalaitzopoulou Vasiliki Bravou Ioannis Lilis Fevronia Angelatou Helen Papadaki Christos D. Georgiou Elisabeth Chroni 《Neurochemical research》2018,43(3):650-658
An ischemia/reperfusion injury of rat’s sciatic nerve was experimentally developed. In this model, we measured the in vivo production of superoxide radical, as a marker of oxidative stress and the occludin expression as an indicator of blood-nerve barrier function and we examined potential protective innervations against these abnormalities. Right sciatic nerves of the animals underwent 3 h of ischemia followed by 7 days of reperfusion and were divided into three groups: ischemic, pretreated with vitamin C in conjunction with vitamin E and treated with tissue plasminogen activator. Compared to measurements from left sciatic nerves used as sham, the ischemic group showed significantly increased superoxide radical and reduced expression of occludin in western blot and immunohistochemistry. No such differences were detected between sham and nerves in the vitamin or tissue plasminogen activator groups. It is suggested that the experimental ischemia/reperfusion model was suitable for studying the relationship between oxidative state and blood-nerve barrier. The reversion of abnormalities by the applied neuroprotective agents might prove to be a clinically important finding in view of the implication of vascular supply derangement in various neuropathies in humans. 相似文献
355.
Analysis of receptor clustering on cell surfaces by imaging fluorescent particles. 总被引:2,自引:1,他引:1 下载免费PDF全文
I E Morrison C M Anderson G N Georgiou G V Stevenson R J Cherry 《Biophysical journal》1994,67(3):1280-1290
Fluorescently labeled low density lipoproteins (LDL) and influenza virus particles were bound to the surface of human fibroblasts and imaged with a cooled slow-scan CCD camera attached to a fluorescence microscope. Particles were also imaged after attachment to polylysine-coated microscope slides. The digital images were analyzed by fitting data points in the region of fluorescent spots by a two-dimensional Gaussian function, thus obtaining a measure of spot intensity with correction for local background. The intensity distributions for particles bound to polylysine slides were mainly accounted for by particle size distributions as determined by electron microscopy. In the case of LDL, the intensity distributions for particles bound to fibroblasts were considerably broadened, indicative of clustering. The on-cell intensity distributions were deconvolved into 1-particle, 2-particle, 3-particle, etc. components using the data obtained with LDL bound to polylysine-coated slides as an empirical measure of the single particle intensity distribution. This procedure yielded a reasonably accurate measure of the proportion of single particles, but large errors were encountered in the proportions of larger cluster sizes. The possibility of studying the dynamics of clustering was investigated by binding LDL to cells at 4 degrees C and observing changes in the intensity distribution with time after warming to 20 degrees C. 相似文献
356.
Degradation of Trichloroethylene by Methanol-Grown Cultures of Methylosinus trichosporium OB3b PP358 总被引:1,自引:0,他引:1 下载免费PDF全文
A soluble methane monooxygenase-constitutive mutant strain of Methylosinus trichosporium OB3b, strain PP358, was grown with methanol as the carbon source, and the kinetics of trichloroethylene (TCE) degradation were determined. PP358 exhibited high TCE degradation rates under both oxygen- and carbon-limiting conditions. The optimal pseudo first-order rate constant for TCE was comparable to the values measured for cells grown with methane. We found that growth under oxygen-limiting conditions results in increased accumulation of polyhydroxybutyrate, which in turn correlates with higher transformation capacities for TCE. It was also shown that methanol inhibits TCE degradation only at high concentrations. Thus, methanol-grown cultures of PP358 represent an efficient system for the biodegradation of chlorinated hydrocarbons. 相似文献
357.
High-throughput screening of enzyme libraries 总被引:8,自引:0,他引:8
Directed evolution is becoming a widely used technique for modifying or enhancing protein performance. Ultimately, the success of directed protein evolution experiments hinges on the efficiency of the methods used to screen libraries for mutants with properties of interest. Although there is still a paucity of general methods for enzyme library screening, in recent years a number of promising strategies have emerged and are increasingly being used to explore challenging issues in protein engineering. 相似文献
358.
359.
Suren A. Gevorgyan Nieves Espinosa Laura Ciammaruchi Bérenger Roth Francesco Livi Stylianos Tsopanidis Simon Züfle Sara Queirós Alberto Gregori Gisele Alves dos Reis Benatto Michael Corazza Morten V. Madsen Markus Hösel Michail J. Beliatis Thue Trofod Larsen‐Olsen Francesco Pastorelli António Castro Alba Mingorance Veniero Lenzi Daniel Fluhr Marta Maria Duarte Ramos Achilleas Savva Luís Silvino Alves Marques Ignasi Burgués Efthymios Georgiou Lucia Serrano‐Luján Frederik C. Krebs 《Liver Transplantation》2016,6(22)
The process of accurately gauging lifetime improvements in organic photovoltaics (OPVs) or other similar emerging technologies, such as perovskites solar cells is still a major challenge. The presented work is part of a larger effort of developing a worldwide database of lifetimes that can help establishing reference baselines of stability performance for OPVs and other emerging PV technologies, which can then be utilized for pass‐fail testing standards and predicting tools. The study constitutes scanning of literature articles related to stability data of OPVs, reported until mid‐2015 and collecting the reported data into a database. A generic lifetime marker is utilized for rating the stability of various reported devices. The collected data is combined with an earlier developed and reported database, which was based on articles reported until mid‐2013. The extended database is utilized for establishing the baselines of lifetime for OPVs tested under different conditions. The work also provides the recent progress in stability of unencapsulated OPVs with different architectures, as well as presents the updated diagram of the reported record lifetimes of OPVs. The presented work is another step forward towards the development of pass‐fail testing standards and lifetime prediction tools for emerging PV technologies. 相似文献
360.
Michelle L. Townsend Angelique Riepsamen Christos Georgiou Victoria M. Flood Peter Caputi Ian M. Wright Warren S. Davis Alison Jones Theresa A. Larkin Moira J. Williamson Brin F. S. Grenyer 《PloS one》2016,11(3)