全文获取类型
收费全文 | 93篇 |
免费 | 4篇 |
专业分类
97篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2019年 | 1篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 9篇 |
2013年 | 3篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有97条查询结果,搜索用时 15 毫秒
71.
The Notch pathway contributes to self-renewal of tumor-initiating cell and inhibition of normal colonic epithelial cell differentiation. Deregulated expression of Notch1 and Jagged1 is observed in colorectal cancer. Hairy/enhancer of split (HES) family, the most characterized targets of Notch, involved in the development of many cancers. In this study, we explored the role of Hes1 in the tumorigenesis of colorectal cancer. Knocking down Hes1 induced CRC cell senescence and decreased the invasion ability, whereas over-expression of Hes1 increased STAT3 phosphorylation activity and up-regulated MMP14 protein level. We further explored the expression of Hes1 in human colorectal cancer and found high Hes1 mRNA expression is associated with poor prognosis in CRC patients. These findings suggest that Hes1 regulates the invasion ability through the STAT3-MMP14 pathway in CRC cells and high Hes1 expression is a predictor of poor prognosis of CRC. 相似文献
72.
A cell-based method for the detection of nanomolar concentrations of bioactive amyloid peptide is described. The method is based upon the observation that fibrillogenic amyloid peptides specifically and dramatically enhance the exocytosis of the intracellular vesicles that are involved in transporting the reduced tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT formazan), with the formation of unique formazan crystals on the cell surface. It is found that the ability of amyloid peptides to induce MTT formazan exocytosis is closely associated with both their neurotoxicity and their ability to activate glia cells, two biological activities of amyloid peptides that are believed to cause neurodegeneration. This simple assay for bioactive amyloid species can be of great value in the screening of anti-amyloid drugs and in the study of amyloid fibrillogenesis with a cell-based model. 相似文献
73.
The role of Bax in glutamate-induced nerve cell death 总被引:4,自引:0,他引:4
The role of the Bax gene product was examined in three forms of cortical nerve cell death in primary cultures. These include spontaneous cell death, oxidative glutamate toxicity, in which exogenous glutamate inhibits cystine uptake resulting in toxic oxidative stress, and ionotropic glutamate receptor-mediated excitotoxicity following a brief exposure to 10 microM glutamate. Primary cortical and hippocampal neuron cultures were established from embryos of Bax -/+ x Bax -/+ matings and the embryos genotyped and assayed for cell death in the three experimental paradigms. Cell death induced by oxidative glutamate toxicity and glutamate-mediated excitotoxicity was not altered in the Bax -/- homozygous knockout animals. In contrast, there was an approximately 50% inhibition of spontaneous cell death. These results suggest that a classical Bax-dependent apoptotic pathway contributes to the spontaneous cell death that takes place when nerve cells are initially exposed to cell culture conditions. A Bax-dependent programmed cell death pathway is not, however, utilized in oxidative glutamate toxicity and NMDA receptor-mediated excitotoxicity following a brief exposure to low concentrations of glutamate. 相似文献
74.
75.
The Uni2 phosphoprotein is a cell cycle regulated component of the basal body maturation pathway in Chlamydomonas reinhardtii 下载免费PDF全文
Piasecki BP LaVoie M Tam LW Lefebvre PA Silflow CD 《Molecular biology of the cell》2008,19(1):262-273
Mutations in the UNI2 locus in Chlamydomonas reinhardtii result in a "uniflagellar" phenotype in which flagellar assembly occurs preferentially from the older basal body and ultrastructural defects reside in the transition zones. The UNI2 gene encodes a protein of 134 kDa that shares 20.5% homology with a human protein. Immunofluorescence microscopy localized the protein on both basal bodies and probasal bodies. The protein is present as at least two molecular-weight variants that can be converted to a single form with phosphatase treatment. Synthesis of Uni2 protein is induced during cell division cycles; accumulation of the phosphorylated form coincides with assembly of transition zones and flagella at the end of the division cycle. Using the Uni2 protein as a cell cycle marker of basal bodies, we observed migration of basal bodies before flagellar resorption in some cells, indicating that flagellar resorption is not required for mitotic progression. We observed the sequential assembly of new probasal bodies beginning at prophase. The uni2 mutants may be defective in the pathways leading to flagellar assembly and to basal body maturation. 相似文献
76.
We investigated placental transport mechanisms of phenylalanine in Macaca mulatta and Macaca fascicularis. In the beginning of the third trimester we administered i.v. phenylalanine and p-chlorophenylalanine to pregnant animals. Initial higher phenylalanine concentrations were observed followed by a rapid decrease in both rhesus mothers and fetuses when compared with phenylalanine levels in fascicularis mothers and fetuses. In general, however, placental transfer mechanisms of phenylalanine did not differ significantly between the two species. 相似文献
77.
Leticia Labriola Maria G Peters Karin Krogh Iván Stigliano Letícia F Terra Cecilia Buchanan Marcel CC Machado Elisa Bal de Kier Joffé Lydia Puricelli Mari C Sogayar 《BMC cell biology》2009,10(1):49-16
Background
The in vitro culture of insulinomas provides an attractive tool to study cell proliferation and insulin synthesis and secretion. However, only a few human beta cell lines have been described, with long-term passage resulting in loss of insulin secretion. Therefore, we set out to establish and characterize human insulin-releasing cell lines. 相似文献78.
79.
Omar Cantillo-Barraza Manuel Medina Sara Zuluaga María Isabel Blanco Rodrigo Caro Jeiczon Jaimes-Dueez Virgilio Beltrn Samanta CC Xavier Omar Triana-Chavez 《PLoS neglected tropical diseases》2021,15(7)
IntroductionUpdating the distribution and natural infection status of triatomine bugs is critical for planning, prioritizing, and implementing strategies to control Chagas disease (CD), especially after vector reduction programs. After carrying out a control program, the Department of Boyaca contains the highest number of Colombian municipalities certified by PAHO to be free of intradomiciliary transmission of Trypanosoma cruzi by Rhodnius prolixus. The present work describes the spatial distribution, natural infection (NI), and molecular characterization of T. cruzi in synanthropic triatomines from the Department of Boyaca in 2017 and 2018.Materials and methodsAn entomological survey was conducted in 52 municipalities in Boyaca known to have had previous infestations of triatomine bugs. Insects were collected through active searches carried out by technical personnel from the Secretary of Health and community members using Triatomine Collection Stations (PITs-acronym in Spanish). For evaluation of natural infection, triatomines were identified morphologically and grouped in pools of one to five individuals of the same species collected in the same household. DNA derived from the feces of each pool of insects was analyzed by PCR for the presence of T. cruzi using primers flanking the satellite DNA of the parasite. SL-IR primers were used to differentiate TCI from the other DTUs and to identify different genotypes. The distribution of the collected triatomines was analyzed to determine any vector hotspots using spatial recreation.ResultsA total of 670 triatomine bugs was collected, belonging to five species: Triatoma dimidiata (73.2%), Triatoma venosa (16.7%), Panstrongylus geniculatus (5.7%), Rhodnius prolixus (4.4%), and Panstrongylus rufotuberculatus (0.4%), from 29 of the 52 municipalities. In total, 71.6% of the bugs were collected within houses (intradomiciliary) and the rest around the houses (peridomiciliary). Triatoma dimidiata was the most widely distributed species and had the highest natural infection index (37.8%), followed by T. venosa and P. geniculatus. TcI was the only DTU found, with the TcI Dom genotype identified in 80% of positive samples and TcI sylvatic in the other insects. Spatial analysis showed clusters of T. dimidiata and T. venosa in the northeast and southwest regions of Boyaca.ConclusionsAfter some municipalities were certified free of natural transmission within houses (intradomiciliary transmission) of T. cruzi by R. prolixus, T. dimidiata has become the most prevalent vector present, and represents a significant risk of resurgent CD transmission. However, T. venosa, P. geniculatus, and P. rufotuberculatus also contribute to the increased risk of transmission. The presence of residual R. prolixus may undo the successes achieved through vector elimination programs. The molecular and spatial analysis used here allows us to identify areas with an ongoing threat of parasite transmission and improve entomological surveillance strategies. 相似文献
80.
Elisangela F Silva Mariana Orsi ?ngela L Andrade Rosana Z Domingues Breno M Silva Helena RC de Araújo Paulo FP Pimenta Michael S Diamond Eliseu SO Rocha Erna G Kroon Luiz CC Malaquias Luiz FL Coelho 《Journal of nanobiotechnology》2012,10(1):1-5