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排序方式: 共有196条查询结果,搜索用时 46 毫秒
161.
The cytotoxicity of dopamine (DA) and 6-hydroxydopamine (6-OHDA) on living cells, in vitro, has been previously deeply investigated in neuroblastoma cells. This study was designed to explore the possibility to use bacteria as targets for studying DA and 6-HODA cytotoxicity. Both DA and 6-HODA oxidize when added to bacteriological media. The rate of autoxidation of 6-HODA was greater than DA within the first hours. The oxidation-dependent cytotoxicity caused bacterial growth-inhibition and killing at concentration of 10(-4)M. All the bacterial strains tested were slightly more susceptible to DA than to 6-HODA. Antioxidants (sodium metabisulfite, cysteine) prevented the oxidation and abolished the growth-inhibitory activity. The addition of exogenous catalase protected the cells against the effect of the oxidation of both the catecholamines up to the concentration of 5 mM, while the addition of exogenous superoxide dismutase protected the cells only at the minimal inhibitory concentrations. Taking into account that some of the results obtained are similar to those previously reported using neuroblastoma cells as targets, the use of bacteria for studying oxygen toxicity from these catecholamines seems to be a potentially useful model system. 相似文献
162.
There has been some evidence that Beh?et's disease (BD) has a significant autoimmune component but the molecular identity
of putative autoantigens has not been well characterized. In the initial analysis of the autoantibody profile in 39 Chinese
BD patients, autoantibodies to cellular proteins were uncovered in 23% as determined by immunoblotting. We have now identified
one of the major autoantibody specificities using expression cloning. Serum from a BD patient was used as a probe to immunoscreen
a λZAP expression cDNA library. Candidate autoantigen cDNAs were characterized by direct nucleotide sequencing and their expressed
products were examined for reactivity to the entire panel of BD sera using immunoprecipitation. Reactivity was also examined
with normal control sera and disease control sera from patients with lupus and Sj?gren's syndrome. Six independent candidate
clones were isolated from the cDNA library screen and were identified as overlapping partial human kinectin cDNAs. The finding
that kinectin was an autoantigen was verified in 9 out of 39 (23%) BD patient sera by immunoprecipitation of the in vitro translation products. Sera from controls showed no reactivity. The significance of kinectin as a participant in autoimmune
pathogenesis in BD and the potential use of autoantibody to kinectin in serodiagnostics are discussed. 相似文献
163.
Crouch JA Glasheen BM Giunta MA Clarke BB Hillman BI 《Fungal genetics and biology : FG & B》2008,45(3):190-206
Mobile transposable elements are among the primary drivers of the evolution of eukaryotic genomes. For fungi, repeat-induced point mutation (RIP) silencing minimizes deleterious effects of transposons by mutating multicopy DNA during meiosis. In this study we identify five transposon species from the mitosporic fungus Colletotrichum cereale and report the signature pattern of RIP acting in a lineage-specific manner on 21 of 35 unique transposon copies, providing the first evidence for sexual recombination for this species. Sequence analysis of genomic populations of the retrotransposon Ccret2 showed repeated rounds of RIP mutation acting on different copies of the element. In the RIPped Ccret2 population, there were multiple inferences of incongruence primarily attributed to RIP-induced homoplasy. This study supports the view that the sequence variability of transposon populations in filamentous fungi reflects the activities of evolutionary processes that fall outside of typical phylogenetic or population genetic reconstructions. 相似文献
164.
Giovanna Di Nardo Enrica Pessione Maria Cavaletto Laura Anfossi Adriano Vanni Fabrizio Briganti Carlo Giunta 《Biometals》2004,17(6):699-706
The different behaviour of two isozymes (IsoA and IsoB) of catechol 1,2-dioxygenase (C1,2O) from Acinetobacter radioresistenss13 on a hydrophobic interaction, Phenyl-Sepharose chromatographic column, prompted us to investigate the role of superficial hydrophobicity on structural-functional aspects for such class of enzymes. The interaction of 8-anilino-1-naphtalenesulphonate (ANS), a fluorescent probe known to bind to hydrophobic sites in proteins, revealed that the two isoenzymes have a markedly different hydrophobicity degree although a similar number of hydrophobic superficial sites were estimated (2.65 for IsoA and 2.18 for IsoB). ANS is easily displaced by adding the substrates catechol or 3-methylcatechol to the adduct, suggesting that the binding sites are in the near surroundings of the catalytic clefts. The analysis of the hydropathy profiles and the possible superficial cavities allowed to recognize the most feasible region for ANS binding.The lower hydrophobicity detected in the near surroundings of the catalytic pocket of IsoB supports its peculiarity to lose the catalytic metal ions more easily than IsoA. As previously suggested for other metalloenzymes, the presence of more hydrophilic and/or smaller residues near to the active site of IsoB is expected to increase the metal ligands mobility thus increasing the metal ion dissociation rate constants, estimated to be 0.078 h–1 and 0.670 h–1 for IsoA and IsoB respectively.
Abbreviations: C1,2O – catechol dioxygenase; ANS – 8-anilino-1-naphthalenesulphonate; PHO – phenol hydroxylase oxygenase 相似文献
165.
Yuyan Zhu Huayan Hou William V. Nikolic Jared Ehrhart Elona Rrapo Paula Bickford Brian Giunta Jun Tan 《PloS one》2008,3(5)
Background
Microglial activation, characterized by p38 MAPK or p44/42 MAPK pathway signal transduction, occurs in Alzheimer''s disease (AD). Our previous studies demonstrated CD45, a membrane-bound protein tyrosine phosphatase (PTP), opposed β-amyloid (Aβ) peptide-induced microglial activation via inhibition of p44/42 MAPK. Additionally we have shown agonism of the RB isoform of CD45 (CD45RB) abrogates lipopolysaccharide (LPS)-induced microglial activation.Methodology and Results
In this study, CD45RB modulation of Aβ peptide or LPS-activated primary cultured microglial cells was further investigated. Microglial cells were co-treated with “aged” FITC-Aβ1–42 and multiple CD45 isoform agonist antibodies. Data revealed cross-linking of CD45, particularly the CD45RB isoform, enhances microglial phagocytosis of Aβ1–42 peptide and inhibits LPS-induced activation of p44/42 and p38 pathways. Co-treatment of microglial cells with agonist CD45 antibodies results in significant inhibition of LPS-induced microglial TNF-α and IL-6 release through p44/42 and/or p38 pathways. Moreover, inhibition of either of these pathways augmented CD45RB cross-linking induced microglial phagocytosis of Aβ1–42 peptide. To investigate the mechanism(s) involved, microglial cells were co-treated with a PTP inhibitor (potassium bisperoxo [1,10-phenanthroline oxovanadate; Phen]) and Aβ1–42 peptides. Data showed synergistic induction of microglial activation as evidenced by TNF-α and IL-6 release; both of which are demonstrated to be dependent on increased p44/42 and/or p38 activation. Finally, it was observed that cross-linking of CD45RB in the presence of Aβ1–42 peptide, inhibits co-localization of microglial MHC class II and Aβ peptide; suggesting CD45 activation inhibits the antigen presenting phenotype of microglial cells.Conclusion
In summary, p38 MAPK is another novel signaling pathway, besides p44/42, in which CD45RB cross-linking negatively regulates microglial Aβ phagocytosis while increasing potentially neurotoxic inflammation. Therefore, agonism of CD45RB PTP activity may be an effective therapeutic target for novel agents to treat AD due to its Aβ lowering, and inflammation reducing, properties that are particularly targeted at microglial cells. Such treatments may be more effective with less potential to produce systemic side-effects than therapeutics which induce non-specific, systemic down-regulation of inflammation. 相似文献166.
Kazuhisa?Nozawa Carlos?A?Casiano John?C?Hamel Christine?Molinaro Marvin?J?Fritzler Edward?KL?ChanEmail author 《Arthritis research & therapy》2002,4(4):R3
Anti-Golgi complex autoantibodies are found primarily in patients with Sjögren's syndrome and systemic lupus erythematosus, although they are not restricted to these diseases. Several Golgi autoantigens have been identified that represent a small family of proteins. Common features of all Golgi autoantigens appear to be their distinct structural organization of multiple α-helical coiled-coil rods in the central domains flanked by non-coiled-coil N-termini and C-termini, and their localization to the cytoplasmic face of Golgi cisternae. Many autoantigens in systemic autoimmune diseases have distinct cleavage products in apoptosis or necrosis and this has raised the possibility that cell death may play a role in the generation of potentially immunostimulatory forms of autoantigens. In the present study, we examined changes in the Golgi complex and associated autoantigens during apoptosis and necrosis. Immunofluorescence analysis showed that the Golgi complex was altered and developed distinctive characteristics during apoptosis and necrosis. In addition, immunoblotting analysis showed the generation of antigenic fragments of each Golgi autoantigen, suggesting that they may play a role in sustaining autoantibody production. Further studies are needed to determine whether the differences observed in the Golgi complex during apoptosis or necrosis may account for the production of anti-Golgi complex autoantibodies. 相似文献
167.
168.
We used Pseudomonas aeruginosa, Burkholderia cepacia and Stenotrophomonas maltophilia, live or heat-killed, isolated from the airways of children with Cystic Fibrosis, to stimulate human neutrophils (PMN) and rat alveolar macrophages (AM) to produce reactive oxygen metabolites in the presence or absence of Curosurf, a natural porcine lung surfactant. We determined: (1) the amount of lipid peroxidation (LPO) as assessed by the amounts of malondialdehyde (MDA) and 4-hydroxyalkenals (4-HNE) using the LPO 586 test kit; (2) the production by AM of superoxide with the nitroblue tetrazolium test and (3) of nitric oxide (NO) with the Griess reaction. Stimulation of PMN or AM increases LPO of Curosurf and cell wall lipids. In both types of phagocytes, B. cepacia induced the highest LPO levels followed by P. aeruginosa and S. maltophilia. PMN, stimulated by live bacteria, induced higher LPO than those stimulated by heat-killed bacteria. B. cepacia stimulated AM to produce more superoxide and NO than did P. aeruginosa and S. maltophilia. The high phagocyte-stimulating ability of B. cepacia and its higher surfactant LPO than those of the other bacteria used in this in vitro study may play a role in vivo in the serious clinical condition known as the "Cepacia syndrome". 相似文献
169.
170.
High performance cloud computing is behind the scene powering “the next big thing” as the mainstream accelerator for innovation in many areas. We describe here how to accelerate inexpensive ARM-based computing nodes with high-end GPGPUs hosted on x86_64 machines using the GVirtuS general-purpose virtualization service. We draw the vision of a possible next generation computing clusters characterized by highly heterogeneous parallelism heading to a lower electric power demanding, less heat producing and more environmental friendliness. Preliminary but promising performance data suggest that this solution could be considered as part of the foundations of the next generation of high performance cloud computing components. 相似文献