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排序方式: 共有391条查询结果,搜索用时 62 毫秒
131.
Thas S. Franceschi Mayara S. P. Soares Nathalia S. Pedra Natlia P. Bona Luiza Spohr Fernanda C. Teixeira Carlus A. T. do Couto Roselia M. Spanevello Marion Deon Carmen R. Vargas Elizandra Braganhol Francieli M. Stefanello 《Amino acids》2020,52(4):629-638
Hypermethioninemia is a disorder characterized by high plasma levels of methionine (Met) and its metabolites such as methionine sulfoxide (MetO). Studies have reported associated inflammatory complications, but the mechanisms involved in the pathophysiology of hypermethioninemia are still uncertain. The present study aims to evaluate the effect of chronic administration of Met and/or MetO on phenotypic characteristics of macrophages, in addition to oxidative stress, purinergic system, and inflammatory mediators in macrophages. In this study, Swiss male mice were subcutaneously injected with Met and MetO at concentrations of 0.35–1.2 g/kg body weight and 0.09–0.3 g/kg body weight, respectively, from the 10th–38th day post-birth, while the control group was treated with saline solution. The results revealed that Met and/or MetO induce an M1/classical activation phenotype associated with increased levels of tumor necrosis factor alpha and nitrite, and reduced arginase activity. It was also found that Met and/or MetO alter the activity of antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, as well as the levels of thiol and reactive oxygen species in macrophages. The chronic administration of Met and/or MetO also promotes alteration in the hydrolysis of ATP and ADP, as indicated by the increased activity of ectonucleotidases. These results demonstrate that chronic administration of Met and/or MetO promotes activated pro-inflammatory profile by inducing M1/classical macrophage polarization. Thus, the changes in redox status and purinergic system upon chronic Met and/or MetO exposure may contribute towards better understanding of the alterations consistent with hypermethioninemic patients. 相似文献
132.
Morphological phylogeny of the Tegulinae (Mollusca: Vetigastropoda) reinforces a Turbinidae position
Ana Paula Dornellas Diogo Ribeiro Couto Luiz Ricardo L. Simone 《Cladistics : the international journal of the Willi Hennig Society》2020,36(2):129-163
A cladistic analysis of the Tegulinae (Turbinidae) is presented using 132 morphological characters and 41 taxa. Tegulinae is recovered and is sister to Prisogaster niger (Prisogasterinae) within the family Turbinidae. This scenario, with Tegulinae as a subfamily within Turbinidae, corroborates with the most molecular analyses. Tegulinae comprises >40 extant species, belonging to eight genera. Morphological studies have not resolved the placement of Tegulinae within Trochoidea sufficiently, and the systematic positions of the genera have never been investigated as a primary objective. The present morphology-based analysis of genus-level relationships within Tegulinae provides a robust, phylogenetic diagnosis of each group, rooted on a firm hypothesis of evolutionary relationships. An additional search was performed to include the tegulines Omphalius nigerrimus and Carolesia blakei terminals using unweighted and implied weighting. Our morphological data provide a solid foundation for ensuing systematic research on Tegulinae, as well as Trochoidea, and evidence facilitating the diagnosis of generic and suprageneric groups. 相似文献
133.
Enzymatic synthesis of Tinuvin 总被引:1,自引:0,他引:1
M. Schroeder L. Pereira Susana Rodríguez Couto A. Erlacher K.-U. Schoening A. Cavaco-Paulo G.M. Guebitz 《Enzyme and microbial technology》2007,40(7):1748-1752
Coupling of 3-(3-tert-butyl-4-hydroxyphenyl) propionic acid methylester to 1H-benzotriazole using a laccase from Trametes hirsuta was studied. The potentially resulting coupling product Tinuvin 1130 is an important UV-absorber used in polymer based materials. Oxidation of the phenol by the laccase led to homomolecular coupling reactions while the laccase did not attack 1H-benzotriazole. Due to the homomolecular reaction of the phenol in the presence of laccase coupling of phenol and 1H-benzotriazole was only observed when 1H-benzotriazole was applied in four-fold molar excess. The reaction was monitored by UV/vis spectroscopy, TLC and MS (ion trap) analysis. Coupling of 1H-benzotriazole took place in ortho position according to the postulated mechanism. 相似文献
134.
Bonatto AC Couto GH Souza EM Araújo LM Pedrosa FO Noindorf L Benelli EM 《Protein expression and purification》2007,55(2):293-299
GlnD is a bifunctional uridylyltransferase/uridylyl-removing enzyme that has a central role in the general nitrogen regulatory system NTR. In enterobacteria, GlnD uridylylates the PII proteins GlnB and GlnK under low levels of fixed nitrogen or ammonium. Under high ammonium levels, GlnD removes UMP from these proteins (deuridylylation). The PII proteins are signal transduction elements that integrate the signals of nitrogen, carbon and energy, and transduce this information to proteins involved in nitrogen metabolism. In Herbaspirillum seropedicae, an endophytic diazotroph isolated from grasses, several genes coding for proteins involved in nitrogen metabolism have been identified and cloned, including glnB, glnK and glnD. In this work, the GlnB, GlnK and GlnD proteins of H. seropedicae were overexpressed in their native forms, purified and used to reconstitute the uridylylation system in vitro. The results show that H. seropedicae GlnD uridylylates GlnB and GlnK trimers producing the forms PII (UMP)(1), PII (UMP)(2) and PII (UMP)(3), in a reaction that requires 2-oxoglutarate and ATP, and is inhibited by glutamine. The quantification of these PII forms indicates that GlnB was more efficiently uridylylated than GlnK in the system used. 相似文献
135.
Joo Paulo Ferreira Rodrigues Thiago Souza Onofre Bruno Couto Barbosa den Ramalho Ferreira Alexis Bonfim‐Melo Nobuko Yoshida 《Cellular microbiology》2019,21(5)
Host cell invasion by Trypanosoma cruzi metacyclic trypomastigote (MT) is mediated by MT‐specific surface molecule gp82, which binds to a still unidentified receptor, inducing lysosome spreading and exocytosis required for the parasitophorous vacuole formation. We examined the involvement of the major lysosome membrane‐associated LAMP proteins in MT invasion. First, human epithelial HeLa cells were incubated with MT in the presence of antibody to LAMP‐1 or LAMP‐2. Antibody to LAMP‐2, but not to LAMP‐1, significantly reduced MT invasion. Next, HeLa cells depleted in LAMP‐1 or LAMP‐2 were generated. Cells deficient in LAMP‐2, but not in LAMP‐1, were significantly more resistant to MT invasion than wild‐type controls. The possibility that LAMP‐2 might be the receptor for gp82 was examined by co‐immunoprecipitation assays. Protein A/G magnetic beads cross‐linked with antibody directed to LAMP‐1 or LAMP‐2 were incubated with HeLa cell and MT detergent extracts. Gp82 bound to LAMP‐2 but not to LAMP‐1. Binding of the recombinant gp82 protein to wild‐type and LAMP‐1‐deficient cells, which was dose dependent and saturable, had a similar profile and was much higher as compared with LAMP‐2‐depleted cells. These data indicate that MT invasion is accomplished through recognition of gp82 by its receptor LAMP‐2. 相似文献
136.
Javier?A. Couto Matthew?P. Vivero Harry?P.W. Kozakewich Amir?H. Taghinia John?B. Mulliken Matthew?L. Warman Arin?K. Greene 《American journal of human genetics》2015,96(3):480-486
Verrucous venous malformation (VVM), also called “verrucous hemangioma,” is a non-hereditary, congenital, vascular anomaly comprised of aberrant clusters of malformed dermal venule-like channels underlying hyperkeratotic skin. We tested the hypothesis that VVM lesions arise as a consequence of a somatic mutation. We performed whole-exome sequencing (WES) on VVM tissue from six unrelated individuals and looked for somatic mutations affecting the same gene in specimens from multiple persons. We observed mosaicism for a missense mutation (, c.1323C>G; NM_002401.3, p.Iso441Met) in mitogen-activated protein kinase kinase kinase 3 (MAP3K3) in three of six individuals. We confirmed the presence of this mutation via droplet digital PCR (ddPCR) in the three subjects and found the mutation in three additional specimens from another four participants. Mutant allele frequencies ranged from 6% to 19% in affected tissue. We did not observe this mutant allele in unaffected tissue or in affected tissue from individuals with other types of vascular anomalies. Studies using global and conditional Map3k3 knockout mice have previously implicated MAP3K3 in vascular development. MAP3K3 dysfunction probably causes VVM in humans. NP_002392相似文献
137.
Rodrigo?S. Pagano Máximo López?Medus Gabriela?E. Gómez Paula?M. Couto María?S. Labanda Lucas Landolfo Cecilia D’Alessio Julio?J. Caramelo 《Biophysical journal》2014,107(3):711-720
Protein aggregation is linked to more than 30 human pathologies, including Alzheimer’s and Parkinson’s diseases. Since small oligomers that form at the beginning of the fibrillation process probably are the most toxic elements, therapeutic strategies involving fibril fragmentation could be detrimental. An alternative approach, named kinetic inhibition, aims to prevent fibril formation by using small ligands that stabilize the parent protein. The factors that govern fibrillation lag times during kinetic inhibition are largely unknown, notwithstanding their importance for designing effective long-term therapies. Inhibitor-bound species are not likely to be incorporated into the core of mature fibrils, although their presence could alter the kinetics of the fibrillation process. For instance, inhibitor-bound species may act as capping elements that impair the nucleation process and/or fibril growth. Here, we address this issue by studying the effect of two natural inhibitors on the fibrillation behavior of lysozyme at neutral pH. We analyzed a set of 79 fibrillation curves obtained in lysozyme alone and a set of 37 obtained in the presence of inhibitors. We calculated the concentrations of the relevant species at the beginning of the curves using the inhibitor-binding constants measured under the same experimental conditions. We found that inhibitor-bound protein species do not affect fibrillation onset times, which are mainly determined by the concentration of unbound protein species present in equilibrium. In this system, knowledge of the fibrillation kinetics and inhibitor affinities suffices to predict the effect of kinetic inhibitors on fibrillation lag times. In addition, we developed a new methodology to better estimate fibrillation lag times from experimental curves. 相似文献
138.
Sabrina do Couto de Miranda Mercedes Bustamante Michael Palace Stephen Hagen Michael Keller Laerte Guimarães Ferreira 《Biotropica》2014,46(2):125-138
The Cerrado, the savanna biome in central Brazil, mostly comprised of woodland savanna, is experiencing intense and fast land use changes. To understand the changes in Cerrado carbon stocks, we present an overview of biomass distribution in different Cerrado vegetation types (i.e., grasslands, shrublands and forestlands). We surveyed 26 studies including 170 Cerrado sites. The grasslands presented mean total biomass of 24 Mg/ha, with 70 percent allocated in the belowground portion. In shrublands, the mean total biomass was 58 Mg/ha being 58 percent in the belowground portion. Finally, in forestlands the mean total biomass was 98 Mg/ha with 18 percent as belowground biomass. The surveyed studies presented 12 allometric equations for biomass estimate, most involving both diameter and height. Data on wood density for Cerrado shrubs and trees are not abundant and the average value was 0.66 g/cm3, similar to that found in the central portion of the Amazon Forest. We also examined the relationship between total precipitation and dry‐season intensity with biomass variation in the Cerrado shrubland using data from tropical rainfall measurement mission (TRMM) for the period 2000–2010. Dry‐season precipitation amount in cerrado areas in severe drought regions explained 29 percent of the variation in aboveground woody biomass. This finding is important in the face of the predictions of longer and more severe dry seasons in the region due to climate change. 相似文献
139.
Mohankrishna Dalvoy Vasudevarao Pushpak Mizar Sujata Kumari Somnath Mandal Soumik Siddhanta Mahadeva MM Swamy Stephanie Kaypee Ravindra C Kodihalli Amrita Banerjee Chandrabhas Naryana Dipak Dasgupta Tapas K. Kundu 《The Journal of biological chemistry》2014,289(11):7702-7717
Hydroxynaphthoquinone-based inhibitors of the lysine acetyltransferase KAT3B (p300), such as plumbagin, are relatively toxic. Here, we report that free thiol reactivity and redox cycling properties greatly contribute to the toxicity of plumbagin. A reactive 3rd position in the naphthoquinone derivatives is essential for thiol reactivity and enhances redox cycling. Using this clue, we synthesized PTK1, harboring a methyl substitution at the 3rd position of plumbagin. This molecule loses its thiol reactivity completely and its redox cycling ability to a lesser extent. Mechanistically, non-competitive, reversible binding of the inhibitor to the lysine acetyltransferase (KAT) domain of p300 is largely responsible for the acetyltransferase inhibition. Remarkably, the modified inhibitor PTK1 was a nearly non-toxic inhibitor of p300. The present report elucidates the mechanism of acetyltransferase activity inhibition by 1,4-naphthoquinones, which involves redox cycling and nucleophilic adduct formation, and it suggests possible routes of synthesis of the non-toxic inhibitor. 相似文献
140.
Maria José Couto Oliveira Fernando do Couto Motta Marilda M Siqueira Paola Cristina Resende Priscilla da Silva Born Thiago Moreno L Souza Milene Mesquita Maria de Lourdes Aguiar Oliveira Sharon Carney Wyller Alencar de Mello Vera Magalh?es 《Memórias do Instituto Oswaldo Cruz》2014,109(7):912-917
After the World Health Organization officially declared the end of the first pandemic
of the XXI century in August 2010, the influenza A(H1N1)pdm09 virus has been
disseminated in the human population. In spite of its sustained circulation, very
little on phylogenetic data or oseltamivir (OST) resistance is available for the
virus in equatorial regions of South America. In order to shed more light on this
topic, we analysed the haemagglutinin (HA) and neuraminidase (NA) genes of influenza
A(H1N1)pdm09 positive samples collected during the pandemic period in the Pernambuco
(PE), a northeastern Brazilian state. Complete HA sequences were compared and amino
acid changes were related to clinical outcome. In addition, the H275Y substitution in
NA, associated with OST resistance, was investigated by pyrosequencing. Samples from
PE were grouped in phylogenetic clades 6 and 7, being clustered together with
sequences from South and Southeast Brazil. The D222N/G HA gene mutation, associated
with severity, was found in one deceased patient that was pregnant. Additionally, the
HA mutation K308E, which appeared in Brazil in 2010 and was only detected worldwide
the following year, was identified in samples from hospitalised cases. The resistance
marker H275Y was not identified in samples tested. However, broader studies are
needed to establish the real frequency of resistance in this Brazilian region. 相似文献