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911.
CC Barros A Haro FJ Russo I Schadock SS Almeida RA Ribeiro EC Vanzela VP Lanzoni FC Barros MR Moraes MA Mori RF Bacurau M Wurtele AC Boschero EM Carneiro M Bader JB Pesquero RC Araujo 《PloS one》2012,7(7):e40573
The Kallikrein-Kinin System (KKS) has been implicated in several aspects of metabolism, including the regulation of glucose homeostasis and adiposity. Kinins and des-Arg-kinins are the major effectors of this system and promote their effects by binding to two different receptors, the kinin B2 and B1 receptors, respectively. To understand the influence of the KKS on the pathophysiology of obesity and type 2 diabetes (T2DM), we generated an animal model deficient for both kinin receptor genes and leptin (obB1B2KO). Six-month-old obB1B2KO mice showed increased blood glucose levels. Isolated islets of the transgenic animals were more responsive to glucose stimulation releasing greater amounts of insulin, mainly in 3-month-old mice, which was corroborated by elevated serum C-peptide concentrations. Furthermore, they presented hepatomegaly, pronounced steatosis, and increased levels of circulating transaminases. This mouse also demonstrated exacerbated gluconeogenesis during the pyruvate challenge test. The hepatic abnormalities were accompanied by changes in the gene expression of factors linked to glucose and lipid metabolisms in the liver. Thus, we conclude that kinin receptors are important for modulation of insulin secretion and for the preservation of normal glucose levels and hepatic functions in obese mice, suggesting a protective role of the KKS regarding complications associated with obesity and T2DM. 相似文献
912.
JA Capitán J Borge-Holthoefer S Gómez J Martinez-Romo L Araujo JA Cuesta A Arenas 《PloS one》2012,7(8):e43694
The size and complexity of actual networked systems hinders the access to a global knowledge of their structure. This fact pushes the problem of navigation to suboptimal solutions, one of them being the extraction of a coherent map of the topology on which navigation takes place. In this paper, we present a Markov chain based algorithm to tag networked terms according only to their topological features. The resulting tagging is used to compute similarity between terms, providing a map of the networked information. This map supports local-based navigation techniques driven by similarity. We compare the efficiency of the resulting paths according to their length compared to that of the shortest path. Additionally we claim that the path steps towards the destination are semantically coherent. To illustrate the algorithm performance we provide some results from the Simple English Wikipedia, which amounts to several thousand of pages. The simplest greedy strategy yields over an 80% of average success rate. Furthermore, the resulting content-coherent paths most often have a cost between one- and threefold compared to shortest-path lengths. 相似文献
913.
Rojas JD Sette LD de Araujo WL Lopes MS da Silva LF Furlan RL Padilla G 《Microbial ecology》2012,63(3):565-577
The chemical ecology and biotechnological potential of metabolites from endophytic and rhizosphere fungi are receiving much
attention. A collection of 17 sugarcane-derived fungi were identified and assessed by PCR for the presence of polyketide synthase
(PKS) genes. The fungi were all various genera of ascomycetes, the genomes of which encoded 36 putative PKS sequences, 26
shared sequence homology with β-ketoacyl synthase domains, while 10 sequences showed homology to known fungal C-methyltransferase
domains. A neighbour–joining phylogenetic analysis of the translated sequences could group the domains into previously established
chemistry-based clades that represented non-reducing, partially reducing and highly reducing fungal PKSs. We observed that,
in many cases, the membership of each clade also reflected the taxonomy of the fungal isolates. The functional assignment
of the domains was further confirmed by in silico secondary and tertiary protein structure predictions. This genome mining
study reveals, for the first time, the genetic potential of specific taxonomic groups of sugarcane-derived fungi to produce
specific types of polyketides. Future work will focus on isolating these compounds with a view to understanding their chemical
ecology and likely biotechnological potential. 相似文献
914.
Juliana Amorim-Conselheiro Lilian Dias Orico Maria Adelaide Galvão-Dias Iraci Martins Grigorio Hildebrando Montenegro Neto Adriana Ruckert Da Rosa Débora Cardoso Oliveira Carlos Pelleschi Taborda Adriana Araujo Reis-Menezes 《Revista iberoamericana de micología》2019,36(2):79-82
BackgroundHistoplasmosis, caused by the dimorphic fungus Histoplasma capsulatum, represents an important public health problem, especially in urban environments where bats and humans cohabit indoors.AimsTo detect the presence of H. capsulatum indoors, using samples of bat droppings collected in roost sites inside houses.MethodsA Real-Time TaqMan PCR assay targeting the ITS1 region of the ribosomal DNA of H. capsulatum was carried out.ResultsFifty-nine sampling points in the municipality of São Paulo were inspected, all of them located at inhabited places. H. capsulatum was isolated from nine samples.ConclusionsThe rapid identification and monitoring of sites where the fungus is present may contribute to make a more reliable database of H. capsulatum distribution. 相似文献
915.
Daniela Requena Suarez Danaë M. A. Rozendaal Veronique De Sy Oliver L. Phillips Esteban Alvarez‐Dvila Kristina Anderson‐Teixeira Alejandro Araujo‐Murakami Luzmila Arroyo Timothy R. Baker Frans Bongers Roel J. W. Brienen Sarah Carter Susan C. Cook‐Patton Ted R. Feldpausch Bronson W. Griscom Nancy Harris Bruno Hrault Eurídice N. Honorio Coronado Sara M. Leavitt Simon L. Lewis Beatriz S. Marimon Abel Monteagudo Mendoza Justin Kassi N'dja Anny Estelle N'Guessan Lourens Poorter Lan Qie Ervan Rutishauser Plinio Sist Bonaventure Sonk Martin J. P. Sullivan Emilio Vilanova Maria M. H. Wang Christopher Martius Martin Herold 《Global Change Biology》2019,25(11):3609-3624
As countries advance in greenhouse gas (GHG) accounting for climate change mitigation, consistent estimates of aboveground net biomass change (?AGB) are needed. Countries with limited forest monitoring capabilities in the tropics and subtropics rely on IPCC 2006 default ?AGB rates, which are values per ecological zone, per continent. Similarly, research into forest biomass change at a large scale also makes use of these rates. IPCC 2006 default rates come from a handful of studies, provide no uncertainty indications and do not distinguish between older secondary forests and old‐growth forests. As part of the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, we incorporate ?AGB data available from 2006 onwards, comprising 176 chronosequences in secondary forests and 536 permanent plots in old‐growth and managed/logged forests located in 42 countries in Africa, North and South America and Asia. We generated ?AGB rate estimates for younger secondary forests (≤20 years), older secondary forests (>20 years and up to 100 years) and old‐growth forests, and accounted for uncertainties in our estimates. In tropical rainforests, for which data availability was the highest, our ?AGB rate estimates ranged from 3.4 (Asia) to 7.6 (Africa) Mg ha?1 year?1 in younger secondary forests, from 2.3 (North and South America) to 3.5 (Africa) Mg ha?1 year?1 in older secondary forests, and 0.7 (Asia) to 1.3 (Africa) Mg ha?1 year?1 in old‐growth forests. We provide a rigorous and traceable refinement of the IPCC 2006 default rates in tropical and subtropical ecological zones, and identify which areas require more research on ?AGB. In this respect, this study should be considered as an important step towards quantifying the role of tropical and subtropical forests as carbon sinks with higher accuracy; our new rates can be used for large‐scale GHG accounting by governmental bodies, nongovernmental organizations and in scientific research. 相似文献
916.
Fumonisins are mycotoxins, produced mainly by Fusarium verticillioides, that are potentially carcinogenic to humans and toxic to animals. Synthesis of these toxins is directed by a cluster of 15 genes, among which FUM1 is the largest; it encodes a polyketide synthase. This enzyme probably catalyzes the synthesis of a polyketide that forms a large portion of the fumonisin structure. In this study, 27 strains possessing the FUM1 gene, as determined by polymerase chain reaction, were analyzed. A portion of the FUM1 gene was amplified and sequenced from 6 of 27 Brazilian strains isolated from corn and sorghum. The sequence similarity for the six F. verticillioides strains was almost 100%. 相似文献
917.
Higuchi DA Barbosa CM Bincoletto C Chagas JR Magalhaes A Richardson M Sanchez EF Pesquero JB Araujo RC Pesquero JL 《Biochimie》2007,89(3):319-328
Two proteins with phospholipase A(2) (PLA(2)) activity were purified to homogeneity from Bothrops leucurus (white-tailed-jararaca) snake venom through three chromatographic steps: Conventional gel filtration on Sephacryl S-200, ion-exchange on Q-Sepharose and reverse phase on Vydac C4 HPLC column. The molecular mass for both enzymes was estimated to be approximately 14 kDa by SDS-PAGE. The N-terminal sequences (48 residues) show that one enzyme presents lysine at position 48 and the other an aspartic acid in this position, and therefore they were designated blK-PLA(2) and blD-PLA(2) respectively. blK-PLA(2) presented negligible levels of PLA(2) activity as compared to that of blD-PLA(2). The PLA(2) activity of both enzymes is Ca(2+)-dependent. blD-PLA(2) did not have any effect upon platelet aggregation induced by arachidonic acid, ADP or collagen, but strongly inhibits coagulation and is able to stimulate Ehrlich tumor growth but not angiogenesis. 相似文献
918.
This paper proposes an extension to the model of a spiking neuron for information processing in artificial neural networks, developing a new approach for the dynamic threshold of the integrate-and-fire neuron. This new approach invokes characteristics of biological neurons such as the behavior of chemical synapses and the receptor field. We demonstrate how such a digital model of spiking neurons can solve complex nonlinear classification with a single neuron, performing experiments for the classical XOR problem. Compared with rate-coded networks and the classical integrate-and-fire model, the trained network demonstrated faster information processing, requiring fewer neurons and shorter learning periods. The extended model validates all the logic functions of biological neurons when such functions are necessary for the proper flow of binary codes through a neural network. 相似文献
919.
Marón LB Covas CP da Silveira NP Pohlmann A Mertins O Tatsuo LN Santanna OA Moro AM Takata CS de Araujo PS da Costa MH 《Journal of liposome research》2007,17(3-4):155-163
Chitosan, alpha-(1-4)-amino-2-deoxy-beta-D-glucan, is a deacetylated form of chitin, an abundant natural polysaccharide present in crustacean shells. Its unique characteristics such as positive charge, biodegradability, biocompatibility, nontoxicity, and rigid linear molecular structure make this macromolecule ideal as drug carrier. The association between chitosan and liposomes was carefully described, where REVs (reverse phase evaporation vesicles) were sandwiched by chitosan. The usage of these particles in vaccine formulation is here proposed for the first time in the literature. The Chitosan-REVs now stabilized by polyvinilic alcohol were the vehicle for Diphtheria toxoid (Dtxd). Round chitosan-sandwiched REVs (REVs-Chi) particles of 373 +/- 17 nm containing 65% Dtxd were obtained. After 200 min of incubation in a simulated gastric fluid, 70% of the Dtxd was liberated from REVs-Chi in comparison to 100% of Dtxd liberated from pure REVs. In PBS, the Dtxd liberation from REVS-Chi was about 60%. Mice were immunized with Dtxd encapsulated within REVs-Chi and with other REVs/Dtxd formulations adsorbed onto Freund adjuvant or alumen [AIF and Al(OH)(3)]. The response patterns and the immune maturity were measured by IgG(1) and IgG(2a) titrations. REVs-Chi containing Dtxd elicited both antibodies production giving the animals higher immune response and selectivity. It was interesting that the memory of those mice immunized with REVs-Chi containing Dtxd enhanced, after booster, antibody production by 47% in contrast with 17 and 7% in mice immunized with the antigen vehiculated in REVs-AIF or REVs-Al(OH)(3), respectively. 相似文献
920.