全文获取类型
收费全文 | 34045篇 |
免费 | 159篇 |
国内免费 | 201篇 |
专业分类
系统科学 | 170篇 |
丛书文集 | 568篇 |
教育与普及 | 52篇 |
理论与方法论 | 113篇 |
现状及发展 | 15855篇 |
研究方法 | 1435篇 |
综合类 | 15739篇 |
自然研究 | 473篇 |
出版年
2013年 | 305篇 |
2012年 | 464篇 |
2011年 | 944篇 |
2010年 | 206篇 |
2008年 | 607篇 |
2007年 | 671篇 |
2006年 | 654篇 |
2005年 | 619篇 |
2004年 | 725篇 |
2003年 | 577篇 |
2002年 | 577篇 |
2001年 | 1085篇 |
2000年 | 1008篇 |
1999年 | 725篇 |
1992年 | 653篇 |
1991年 | 488篇 |
1990年 | 549篇 |
1989年 | 553篇 |
1988年 | 524篇 |
1987年 | 614篇 |
1986年 | 546篇 |
1985年 | 685篇 |
1984年 | 552篇 |
1983年 | 427篇 |
1982年 | 399篇 |
1981年 | 449篇 |
1980年 | 528篇 |
1979年 | 1083篇 |
1978年 | 905篇 |
1977年 | 860篇 |
1976年 | 714篇 |
1975年 | 754篇 |
1974年 | 1004篇 |
1973年 | 886篇 |
1972年 | 924篇 |
1971年 | 1014篇 |
1970年 | 1285篇 |
1969年 | 971篇 |
1968年 | 969篇 |
1967年 | 954篇 |
1966年 | 822篇 |
1965年 | 568篇 |
1964年 | 182篇 |
1959年 | 289篇 |
1958年 | 523篇 |
1957年 | 356篇 |
1956年 | 314篇 |
1955年 | 288篇 |
1954年 | 295篇 |
1948年 | 203篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
111.
112.
Larrucea S Butta N Rodriguez RB Alonso-Martin S Arias-Salgado EG Ayuso MS Parrilla R 《Cellular and molecular life sciences : CMLS》2007,64(22):2965-2974
Podocalyxin (PODXL) is a mucin protein of the CD34 family expressed in kidney glomerular podocytes, vascular endothelium,
progenitor bone marrow and tumor cells. It is assumed that PODXL plays an anti-adherent role in kidney podocytes. CHO cells
stably expressing human PODXL (CHO-PODXL) or human tumor cells (Tera-1) inherently expressing PODXL showed increased adherence
to platelets. The adherence of cells was inhibited (70%) by blockers of platelet P-selectin, prevented by the soluble ectodomain
of human PODXL (PODXL-Δ) or by the arginine-glycine-aspartate (RGDS) peptide and partially impeded by inhibition of integrin
αVβ3/αVβ5, suggesting a coordinated action of P-selectin and integrins. Colocalization of platelet P-selectin and PODXL expressed
on CHO cells was demonstrated by confocal immunofluorescence. No adherence to platelets was observed when PODXL was expressed
in glycomutant CHO cells deficient in sialic acid.
Received 14 August 2007; received after revision 12 September 2007; accepted 13 September 2007 相似文献
113.
114.
115.
Dina C Meyre D Gallina S Durand E Körner A Jacobson P Carlsson LM Kiess W Vatin V Lecoeur C Delplanque J Vaillant E Pattou F Ruiz J Weill J Levy-Marchal C Horber F Potoczna N Hercberg S Le Stunff C Bougnères P Kovacs P Marre M Balkau B Cauchi S Chèvre JC Froguel P 《Nature genetics》2007,39(6):724-726
We identified a set of SNPs in the first intron of the FTO (fat mass and obesity associated) gene on chromosome 16q12.2 that is consistently strongly associated with early-onset and severe obesity in both adults and children of European ancestry with an experiment-wise P value of 1.67 x 10(-26) in 2,900 affected individuals and 5,100 controls. The at-risk haplotype yields a proportion of attributable risk of 22% for common obesity. We conclude that FTO contributes to human obesity and hence may be a target for subsequent functional analyses. 相似文献
116.
Liu F Thirumangalathu S Gallant NM Yang SH Stoick-Cooper CL Reddy ST Andl T Taketo MM Dlugosz AA Moon RT Barlow LA Millar SE 《Nature genetics》2007,39(1):106-112
Fungiform taste papillae form a regular array on the dorsal tongue. Taste buds arise from papilla epithelium and, unusually for epithelial derivatives, synapse with neurons, release neurotransmitters and generate receptor and action potentials. Despite the importance of taste as one of our five senses, genetic analyses of taste papilla and bud development are lacking. We demonstrate that Wnt-beta-catenin signaling is activated in developing fungiform placodes and taste bud cells. A dominant stabilizing mutation of epithelial beta-catenin causes massive overproduction of enlarged fungiform papillae and taste buds. Likewise, genetic deletion of epithelial beta-catenin or inhibition of Wnt-beta-catenin signaling by ectopic dickkopf1 (Dkk1) blocks initiation of fungiform papilla morphogenesis. Ectopic papillae are innervated in the stabilizing beta-catenin mutant, whereas ectopic Dkk1 causes absence of lingual epithelial innervation. Thus, Wnt-beta-catenin signaling is critical for fungiform papilla and taste bud development. Altered regulation of this pathway may underlie evolutionary changes in taste papilla patterning. 相似文献
117.
118.
119.
The role of hypoxia-inducible factors in cancer 总被引:7,自引:0,他引:7