全文获取类型
收费全文 | 226篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
系统科学 | 7篇 |
教育与普及 | 1篇 |
现状及发展 | 11篇 |
研究方法 | 39篇 |
综合类 | 170篇 |
出版年
2012年 | 24篇 |
2011年 | 24篇 |
2010年 | 6篇 |
2009年 | 1篇 |
2008年 | 12篇 |
2007年 | 12篇 |
2006年 | 14篇 |
2005年 | 12篇 |
2004年 | 14篇 |
2003年 | 18篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1977年 | 1篇 |
1971年 | 5篇 |
1970年 | 8篇 |
1966年 | 1篇 |
1959年 | 2篇 |
1958年 | 9篇 |
1957年 | 3篇 |
1956年 | 4篇 |
1955年 | 3篇 |
1954年 | 3篇 |
1948年 | 4篇 |
1947年 | 1篇 |
排序方式: 共有228条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
Sugar transporters for intercellular exchange and nutrition of pathogens 总被引:10,自引:0,他引:10
Chen LQ Hou BH Lalonde S Takanaga H Hartung ML Qu XQ Guo WJ Kim JG Underwood W Chaudhuri B Chermak D Antony G White FF Somerville SC Mudgett MB Frommer WB 《Nature》2010,468(7323):527-532
Sugar efflux transporters are essential for the maintenance of animal blood glucose levels, plant nectar production, and plant seed and pollen development. Despite broad biological importance, the identity of sugar efflux transporters has remained elusive. Using optical glucose sensors, we identified a new class of sugar transporters, named SWEETs, and show that at least six out of seventeen Arabidopsis, two out of over twenty rice and two out of seven homologues in Caenorhabditis elegans, and the single copy human protein, mediate glucose transport. Arabidopsis SWEET8 is essential for pollen viability, and the rice homologues SWEET11 and SWEET14 are specifically exploited by bacterial pathogens for virulence by means of direct binding of a bacterial effector to the SWEET promoter. Bacterial symbionts and fungal and bacterial pathogens induce the expression of different SWEET genes, indicating that the sugar efflux function of SWEET transporters is probably targeted by pathogens and symbionts for nutritional gain. The metazoan homologues may be involved in sugar efflux from intestinal, liver, epididymis and mammary cells. 相似文献
105.
Familial dyserythropoietic anaemia and thrombocytopenia due to an inherited mutation in GATA1 总被引:20,自引:0,他引:20
Nichols KE Crispino JD Poncz M White JG Orkin SH Maris JM Weiss MJ 《Nature genetics》2000,24(3):266-270
Haematopoietic development is regulated by nuclear protein complexes that coordinate lineage-specific patterns of gene expression. Targeted mutagenesis in embryonic stem cells and mice has revealed roles for the X-linked gene Gata1 in erythrocyte and megakaryocyte differentiation. GATA-1 is the founding member of a family of DNA-binding proteins that recognize the motif WGATAR through a conserved multifunctional domain consisting of two C4-type zinc fingers. Here we describe a family with X-linked dyserythropoietic anaemia and thrombocytopenia due to a substitution of methionine for valine at amino acid 205 of GATA-1. This highly conserved valine is necessary for interaction of the amino-terminal zinc finger of GATA-1 with its essential cofactor, FOG-1 (for friend of GATA-1; refs 9-12). We show that the V205M mutation abrogates the interaction between Gata-1 and Fog-1, inhibiting the ability of Gata-1 to rescue erythroid differentiation in an erythroid cell line deficient for Gata-1 (G1E). Our findings underscore the importance of FOG-1:Gata-1 associations in both megakaryocyte and erythroid development, and suggest that other X-linked anaemias or thrombocytopenias may be caused by defects in GATA1. 相似文献
106.
Rapley EA Crockford GP Teare D Biggs P Seal S Barfoot R Edwards S Hamoudi R Heimdal K Fossâ SD Tucker K Donald J Collins F Friedlander M Hogg D Goss P Heidenreich A Ormiston W Daly PA Forman D Oliver TD Leahy M Huddart R Cooper CS Bodmer JG Easton DF Stratton MR Bishop DT 《Nature genetics》2000,24(2):197-200
Testicular germ-cell tumours (TGCT) affect 1 in 500 men and are the most common cancer in males aged 15-40 in Western European populations. The incidence of TGCT has risen dramatically over the last century. Known risk factors for TGCT include a history of undescended testis (UDT), testicular dysgenesis, infertility, previously diagnosed TGCT (ref. 7) and a family history of the disease. Brothers of men with TGCT have an 8-10-fold risk of developing TGCT (refs 8,9), whereas the relative risk to fathers and sons is fourfold (ref. 9). This familial relative risk is much higher than that for most other types of cancer. We have collected samples from 134 families with two or more cases of TGCT, 87 of which are affected sibpairs. A genome-wide linkage search yielded a heterogeneity lod (hlod) score of 2.01 on chromosome Xq27 using all families compatible with X inheritance. We obtained a hlod score of 4.7 from families with at least one bilateral case, corresponding to a genome-wide significance level of P=0.034. The proportion of families with UDT linked to this locus was 73% compared with 26% of families without UDT (P=0.03). Our results provide evidence for a TGCT susceptibility gene on chromosome Xq27 that may also predispose to UDT. 相似文献
107.
108.
109.
110.
Lightning observations by satellite 总被引:3,自引:0,他引:3