全文获取类型
收费全文 | 78篇 |
免费 | 1篇 |
国内免费 | 4篇 |
专业分类
教育与普及 | 1篇 |
理论与方法论 | 2篇 |
现状及发展 | 14篇 |
研究方法 | 15篇 |
综合类 | 49篇 |
自然研究 | 2篇 |
出版年
2022年 | 1篇 |
2016年 | 2篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2012年 | 7篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2008年 | 3篇 |
2007年 | 10篇 |
2006年 | 10篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1970年 | 1篇 |
1960年 | 1篇 |
1947年 | 1篇 |
1946年 | 1篇 |
排序方式: 共有83条查询结果,搜索用时 0 毫秒
81.
Remodelling its shape, or morphogenesis, is a fundamental property of living tissue. It underlies much of embryonic development and numerous pathologies. Convergent extension (CE) of the axial mesoderm of vertebrates is an intensively studied model for morphogenetic processes that rely on cell rearrangement. It involves the intercalation of polarized cells perpendicular to the antero-posterior (AP) axis, which narrows and lengthens the tissue. Several genes have been identified that regulate cell behaviour underlying CE in zebrafish and Xenopus. Many of these are homologues of genes that control epithelial planar cell polarity in Drosophila. However, elongation of axial mesoderm must be also coordinated with the pattern of AP tissue specification to generate a normal larval morphology. At present, the long-range control that orients CE with respect to embryonic axes is not understood. Here we show that the chordamesoderm of Xenopus possesses an intrinsic AP polarity that is necessary for CE, functions in parallel to Wnt/planar cell polarity signalling, and determines the direction of tissue elongation. The mechanism that establishes AP polarity involves graded activin-like signalling and directly links mesoderm AP patterning to CE. 相似文献
82.
Jackson-Grusby L Beard C Possemato R Tudor M Fambrough D Csankovszki G Dausman J Lee P Wilson C Lander E Jaenisch R 《Nature genetics》2001,27(1):31-39
Cytosine methylation of mammalian DNA is essential for the proper epigenetic regulation of gene expression and maintenance of genomic integrity. To define the mechanism through which demethylated cells die, and to establish a paradigm for identifying genes regulated by DNA methylation, we have generated mice with a conditional allele for the maintenance DNA methyltransferase gene Dnmt1. Cre-mediated deletion of Dnmt1 causes demethylation of cultured fibroblasts and a uniform p53-dependent cell death. Mutational inactivation of Trp53 partially rescues the demethylated fibroblasts for up to five population doublings in culture. Oligonucleotide microarray analysis showed that up to 10% of genes are aberrantly expressed in demethylated fibroblasts. Our results demonstrate that loss of Dnmt1 causes cell-type-specific changes in gene expression that impinge on several pathways, including expression of imprinted genes, cell-cycle control, growth factor/receptor signal transduction and mobilization of retroelements. 相似文献
83.
Rampoldi L Dobson-Stone C Rubio JP Danek A Chalmers RM Wood NW Verellen C Ferrer X Malandrini A Fabrizi GM Brown R Vance J Pericak-Vance M Rudolf G Carrè S Alonso E Manfredi M Németh AH Monaco AP 《Nature genetics》2001,28(2):119-120
Chorea-acanthocytosis (CHAC, MIM 200150) is an autosomal recessive neurodegenerative disorder characterized by the gradual onset of hyperkinetic movements and abnormal erythrocyte morphology (acanthocytosis). Neurological findings closely resemble those observed in Huntington disease. We identified a gene in the CHAC critical region and found 16 different mutations in individuals with chorea-acanthocytosis. CHAC encodes an evolutionarily conserved protein that is probably involved in protein sorting. 相似文献