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排序方式: 共有108条查询结果,搜索用时 15 毫秒
91.
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Cloning and expression of genes for the Oxytricha telomere-binding protein: specific subunit interactions in the telomeric complex. 总被引:19,自引:0,他引:19
Telomeres of Oxytricha nova macronuclear chromosomes consist of a repeated T4G4 sequence, single-stranded at the 3' terminus, bound by a heterodimeric protein. The cloning of genes for the two polypeptides and their separate expression in E. coli have enabled evaluation of their individual contributions to DNA binding. The 56 kd alpha subunit binds single-stranded DNA by itself, one polypeptide per T4G4 block; multiple subunits can coat a (T4G4)n multimer. The derived amino acid sequence of alpha does not reveal any known DNA-binding motif, so it appears to represent a novel type of DNA-binding protein. The previously cloned 41 kd beta subunit does not by itself protect DNA from methylation, but is required along with alpha to recreate the pattern of methylation protection indicative of telomeres in vivo. The unusual ability of the protein to engage in two different interactions with the same telomeric DNA sequence might provide the versatility necessary for diverse telomere functions. 相似文献
94.
Zimmerman PA; Katholi CR; Wooten MC; Lang-Unnasch N; Unnasch TR 《Molecular biology and evolution》1994,11(3):384-392
Polymerase chain reaction (PCR) products were characterized for a repeated
sequence family (designated "O-150") of the human filarial parasite
Onchocerca volvulus. In phylogenetic inferences, the O-150 sequences
clustered into closely related groups, suggesting that concerted evolution
maintains sequence homology in this family. Using a novel mathematical
model based on a nested application of an analysis of variance, we
demonstrated that African rainforest and savannah strain parasite
populations are significantly different. In contrast, parasites collected
in the New World are indistinguishable from African savannah strains of O.
volvulus. This finding supports the hypothesis that onchocerciasis was
recently introduced into the New World, possibly as a result of the slave
trade.
相似文献
95.
Cadmium (Cd) is an industrial and environmental pollutant that produces toxic effects on gametogenesis, pre- and post-implantation embryos, and the placenta. Because the effects of acute Cd intoxication on the placenta are not well understood, we investigated changes in its glycosylated components in Cd treated dams at days 4, 7, 10 and 15 of gestation using lectin histochemistry. CdCl2 was administered to pregnant rats; control animals received sterile normal saline. Placentas were processed for DBA, Con A, SBA, PNA, UEA-I, RCA-I and WGA lectin histochemistry to evaluate changes in the carbohydrate pattern of the placenta that might modify cell interactions and contribute to embryonic alterations. Lectin binding was analyzed in the yolk sac; trophoblast giant cells; trophoblast I, II and III; spongiotrophoblast cells and endovascular trophoblast cells in the chorioallantoic placenta. Our lectin binding patterns showed that Cd caused alteration of SBA and DBA labeling of trophoblast-derived cells, which suggested increased expressions of α and β GalNAc. Cd also caused decreased UEA-1 binding affinity, which indicated fewer α-L-Fuc residues in placentas of Cd treated dams. The nonreactivity in trophoblast I of the control placentas incubated with Con-A contrasted with the labeling in placentas of experimental dams, which indicated increased expression of terminal α-D-Man, and α-D-Glc residues. We found that Cd altered the reactivity of placenta to several lectins, which indicated modification of the glycotype presented by the fetal component of the placenta. We report that Cd exerts a deleterious effect on the glycosylation pattern of the placenta. 相似文献
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97.
K Shahzad A Fatima M Cadeiras N Wisniewski G Bondar R Cheng E Reed MC Deng 《Current Genomics》2012,13(4):334-341
In the post-genome era, high throughput gene expression profiling has been successfully used to develop genomic biomarker panels (GBP) that can be integrated into clinical decision making. The development of GBPs in the context of personalized medicine is a scientifically challenging and resource-intense process. It needs to be accomplished in a systematic phased approach to address biological variation related to a clinical phenotype (e.g. disease etiology, gender, etc.) and minimize technical variation (noise). Here we present the methodological aspects of GBP development based on the experience of the Cardiac Allograft Rejection Gene Expression Observation (CARGO) study, a study that lead to the development of a molecular classifier for rejection screening in heart transplant patients. 相似文献
98.
Willeke MC van Roon-Mom Barry A Pepers Peter AC 't Hoen Carola ACM Verwijmeren Johan T den Dunnen Josephine C Dorsman GertJan B van Ommen 《BMC molecular biology》2008,9(1):84
Background
Huntington's disease is a progressive autosomal dominant neurodegenerative disorder that is caused by a CAG repeat expansion in the HD or Huntington's disease gene. Although micro array studies on patient and animal tissue provide valuable information, the primary effect of mutant huntingtin will inevitably be masked by secondary processes in advanced stages of the disease. Thus, cell models are instrumental to study early, direct effects of mutant huntingtin. mRNA changes were studied in an inducible PC12 model of Huntington's disease, before and after aggregates became visible, to identify groups of genes that could play a role in the early pathology of Huntington's disease. 相似文献99.
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