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101.
Aquatic Ecology - Potamon potamios populations have decreased significantly due to the degradation of its habitat caused by human activities, mainly the use of insecticides. Today, P. potamios is... 相似文献
102.
McCaffrey K Boo I Tewierek K Edmunds ML Poumbourios P Drummer HE 《Journal of virology》2012,86(7):3961-3974
Hepatitis C virus glycoprotein E2 contains 18 conserved cysteines predicted to form nine disulfide pairs. In this study, a comprehensive cysteine-alanine mutagenesis scan of all 18 cysteine residues was performed in E1E2-pseudotyped retroviruses (HCVpp) and recombinant E2 receptor-binding domain (E2 residues 384 to 661 [E2(661)]). All 18 cysteine residues were absolutely required for HCVpp entry competence. The phenotypes of individual cysteines and pairwise mutation of disulfides were largely the same for retrovirion-incorporated E2 and E2(661), suggesting their disulfide arrangements are similar. However, the contributions of each cysteine residue and the nine disulfides to E2 structure and function varied. Individual Cys-to-Ala mutations revealed discordant effects, where removal of one Cys within a pair had minimal effect on H53 recognition and CD81 binding (C486 and C569) while mutation of its partner abolished these functions (C494 and C564). Removal of disulfides at C581-C585 and C452-C459 significantly reduced the amount of E1 coprecipitated with E2, while all other disulfides were absolutely required for E1E2 heterodimerization. Remarkably, E2(661) tolerates the presence of four free cysteines, as simultaneous mutation of C452A, C486A, C569A, C581A, C585A, C597A, and C652A (M+C597A) retained wild-type CD81 binding. Thus, only one disulfide from each of the three predicted domains, C429-C552 (DI), C503-C508 (DII), and C607-C644 (DIII), is essential for the assembly of the E2(661) CD81-binding site. Furthermore, the yield of total monomeric E2 increased to 70% in M+C597A. These studies reveal the contribution of each cysteine residue and the nine disulfide pairs to E2 structure and function. 相似文献
103.
104.
Aristidis S. Veskoukis Michalis G. Nikolaidis Antonios Kyparos Dimitrios Kouretas 《Free radical biology & medicine》2009,47(10):1371-1374
This study investigated whether selected oxidative stress markers measured in blood adequately reflect redox status in skeletal muscle, heart, and liver. Several markers were determined after implementing two treatments known to affect redox status, namely exercise and allopurinol administration. Xanthine oxidase, thiobarbituric acid-reactive substances (TBARS), protein carbonyls (PC), reduced glutathione (GSH), oxidized glutathione (GSSG), catalase, and total antioxidant capacity were determined in blood, skeletal muscle, heart, and liver. Correlation between blood and tissues in each marker was performed through the Spearman rank correlation coefficient. GSSG in erythrocytes was correlated with all tissues, ranging in the five experimental groups as follows: skeletal muscle rs = 0.656–0.874, heart rs = 0.742–0.981, liver rs = 0.646–0.855. Xanthine oxidase and TBARS measured in blood satisfactorily described the redox status of the heart (0.753–0.964 and 0.705–1.000, respectively) and liver (0.755–0.902 and 0.656–1.000, respectively). Skeletal muscle and heart redox status can be adequately described by PC (0.652–1.000 and 0.656–0.964, respectively), GSH (0.693–1.000 and 0.656–1.000, respectively), and catalase (0.745–1.000 and 0.656–1.000, respectively) measured in blood. In conclusion, this study suggests that a combination of markers measured in blood provides a reliable indication about the redox status in skeletal muscle, heart, and liver. 相似文献
105.
Vasiliki Koliaraki Martha Marinou Theodoros P. Vassilakopoulos Eustathios Vavourakis Emmanuel Tsochatzis Gerassimos A. Pangalis George Papatheodoridis Alexandra Stamoulakatou Dorine W. Swinkels George Papanikolaou Avgi Mamalaki 《PloS one》2009,4(2)
Background
Hepcidin is a 25-aminoacid cysteine-rich iron regulating peptide. Increased hepcidin concentrations lead to iron sequestration in macrophages, contributing to the pathogenesis of anaemia of chronic disease whereas decreased hepcidin is observed in iron deficiency and primary iron overload diseases such as hereditary hemochromatosis. Hepcidin quantification in human blood or urine may provide further insights for the pathogenesis of disorders of iron homeostasis and might prove a valuable tool for clinicians for the differential diagnosis of anaemia. This study describes a specific and non-operator demanding immunoassay for hepcidin quantification in human sera.Methods and Findings
An ELISA assay was developed for measuring hepcidin serum concentration using a recombinant hepcidin25-His peptide and a polyclonal antibody against this peptide, which was able to identify native hepcidin. The ELISA assay had a detection range of 10–1500 µg/L and a detection limit of 5.4 µg/L. The intra- and interassay coefficients of variance ranged from 8–15% and 5–16%, respectively. Mean linearity and recovery were 101% and 107%, respectively. Mean hepcidin levels were significantly lower in 7 patients with juvenile hemochromatosis (12.8 µg/L) and 10 patients with iron deficiency anemia (15.7 µg/L) and higher in 7 patients with Hodgkin lymphoma (116.7 µg/L) compared to 32 age-matched healthy controls (42.7 µg/L).Conclusions
We describe a new simple ELISA assay for measuring hepcidin in human serum with sufficient accuracy and reproducibility. 相似文献106.
Evangelos J. Giamarellos-Bourboulis Maria Raftogiannis Anastasia Antonopoulou Fotini Baziaka Pantelis Koutoukas Athina Savva Theodora Kanni Marianna Georgitsi Aikaterini Pistiki Thomas Tsaganos Nikolaos Pelekanos Sofia Athanassia Labrini Galani Efthymia Giannitsioti Dimitra Kavatha Flora Kontopidou Maria Mouktaroudi Garyfallia Poulakou Vissaria Sakka Periklis Panagopoulos Antonios Papadopoulos Kyriaki Kanellakopoulou Helen Giamarellou 《PloS one》2009,4(12)
Background
The pandemic by the novel H1N1 virus has created the need to study any probable effects of that infection in the immune system of the host.Methodology/Principal Findings
Blood was sampled within the first two days of the presentation of signs of infection from 10 healthy volunteers; from 18 cases of flu-like syndrome; and from 31 cases of infection by H1N1 confirmed by reverse RT-PCR. Absolute counts of subtypes of monocytes and of lymphocytes were determined after staining with monoclonal antibodies and analysis by flow cytometry. Peripheral blood mononuclear cells (PBMCs) were isolated from patients and stimulated with various bacterial stimuli. Concentrations of tumour necrosis factor-alpha, interleukin (IL)-1beta, IL-6, IL-18, interferon (FN)-alpha and of IFN-gamma were estimated in supernatants by an enzyme immunoassay. Infection by H1N1 was accompanied by an increase of monocytes. PBMCs of patients evoked strong cytokine production after stimulation with most of bacterial stimuli. Defective cytokine responses were shown in response to stimulation with phytohemagglutin and with heat-killed Streptococcus pneumoniae. Adaptive immune responses of H1N1-infected patients were characterized by decreases of CD4-lymphocytes and of B-lymphocytes and by increase of T-regulatory lymphocytes (Tregs).Conclusions/Significance
Infection by the H1N1 virus is accompanied by a characteristic impairment of the innate immune responses characterized by defective cytokine responses to S.pneumoniae. Alterations of the adaptive immune responses are predominated by increase of Tregs. These findings signify a predisposition for pneumococcal infections after infection by H1N1 influenza. 相似文献107.
Emmanuel Dialynas Pantelis Topalis John Vontas Christos Louis 《PLoS neglected tropical diseases》2009,3(6)
Background
Monitoring of insect vector populations with respect to their susceptibility to one or more insecticides is a crucial element of the strategies used for the control of arthropod-borne diseases. This management task can nowadays be achieved more efficiently when assisted by IT (Information Technology) tools, ranging from modern integrated databases to GIS (Geographic Information System). Here we describe an application ontology that we developed de novo, and a specially designed database that, based on this ontology, can be used for the purpose of controlling mosquitoes and, thus, the diseases that they transmit.Methodology/Principal Findings
The ontology, named MIRO for Mosquito Insecticide Resistance Ontology, developed using the OBO-Edit software, describes all pertinent aspects of insecticide resistance, including specific methodology and mode of action. MIRO, then, forms the basis for the design and development of a dedicated database, IRbase, constructed using open source software, which can be used to retrieve data on mosquito populations in a temporally and spatially separate way, as well as to map the output using a Google Earth interface. The dependency of the database on the MIRO allows for a rational and efficient hierarchical search possibility.Conclusions/Significance
The fact that the MIRO complies with the rules set forward by the OBO (Open Biomedical Ontologies) Foundry introduces cross-referencing with other biomedical ontologies and, thus, both MIRO and IRbase are suitable as parts of future comprehensive surveillance tools and decision support systems that will be used for the control of vector-borne diseases. MIRO is downloadable from and IRbase is accessible at VectorBase, the NIAID-sponsored open access database for arthropod vectors of disease. 相似文献108.
Petsalakis EI Chrysina ED Tiraidis C Hadjiloi T Leonidas DD Oikonomakos NG Aich U Varghese B Loganathan D 《Bioorganic & medicinal chemistry》2006,14(15):5316-5324
N-acetyl-beta-D-glucopyranosylamine (NAG) is a potent inhibitor (Ki=32 microM) of glycogen phosphorylase b (GPb), and has been employed as a lead compound for the structure-based design of new analogues, in an effort to utilize its potential as a hypoglycaemic agent. Replacement of the acetamido group by azidoacetamido group resulted in an inhibitor, N-azidoacetyl-beta-D-glucopyranosylamine (azido-NAG), with a Ki value of 48.7 microM, in the direction of glycogen synthesis. In order to elucidate the mechanism of inhibition, we determined the ligand structure in complex with GPb at 2.03 A resolution, and the structure of the fully acetylated derivative in the free form. The molecular packing of the latter is stabilized by a number of bifurcated hydrogen bonds of which the one involving a bifurcated C-H...N...H-C type hydrogen bonding is rather unique in organic azides. Azido-NAG can be accommodated in the catalytic site of T-state GPb at approximately the same position as that of NAG and stabilizes the T-state conformation of the 280 s loop by making several favourable contacts to residues of this loop. The difference observed in the Ki values of the two analogues can be interpreted in terms of desolvation effects, subtle structural changes of protein residues and changes in water structure. 相似文献
109.
Nikolaos Paralikidis Nikolaos Papageorgiou Apostolos Tsiompanoudis Loizos Konstantinou Theodoros Christakis 《European Journal of Wildlife Research》2010,56(1):89-93
Using stomach content analysis, we studied the diet of the Black Francolin (Francolinus francolinus) on the island of Cyprus during November and December of 2004 and 2005. The purpose of this study was to estimate the most
important sources of food on its diet. Stomachs of Black Francolins were obtained from two study areas on Cyprus. We sampled
53 freshly hunter-killed specimens for dietary analysis. Our results showed that dietary intake reflected a generalist and
omnivorous diet with seeds of cultivated crops and insects of the Coleoptera and Hymenoptera orders being the most commonly
identified. Differences in food composition between the two study areas reflected differences in land use, suggesting that
human management of Black Francolin habitat is critical in understanding and managing this important game species. 相似文献
110.