全文获取类型
收费全文 | 140篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
159篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 4篇 |
2012年 | 8篇 |
2011年 | 4篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 3篇 |
2007年 | 13篇 |
2006年 | 8篇 |
2005年 | 10篇 |
2004年 | 3篇 |
2003年 | 12篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 1篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有159条查询结果,搜索用时 0 毫秒
31.
Trudy FC Mackay 《Genome biology》2000,1(4):reports4018.1-reports40186
A report on the Third Genetic Effects on Aging Meeting, The Jackson Laboratory, Bar Harbor, Maine, August 4-8, 2000. 相似文献
32.
33.
34.
Matzke A Churakov G Berkes P Arms EM Kelsey D Brosius J Kriegs JO Schmitz J 《Molecular biology and evolution》2012,29(6):1497-1501
More than 150 Ma, the avian lineage separated from that of other dinosaurs and later diversified into the more than 10,000 species extant today. The early neoavian bird radiations most likely occurred in the late Cretaceous (more than 65 Ma) but left behind few if any molecular signals of their archaic evolutionary past. Retroposed elements, once established in an ancestral population, are highly valuable, virtually homoplasy-free markers of species evolution; after applying stringent orthology criteria, their phylogenetically informative presence/absence patterns are free of random noise and independent of evolutionary rate or nucleotide composition effects. We screened for early neoavian orthologous retroposon insertions and identified six markers with conflicting presence/absence patterns, whereas six additional retroposons established before or after the presumed major neoavian radiation show consistent phylogenetic patterns. The exceptionally frequent conflicting retroposon presence/absence patterns of neoavian orders are strong indicators of an extensive incomplete lineage sorting era, potentially induced by an early rapid successive speciation of ancestral Neoaves. 相似文献
35.
Numerous studies have investigated specific pathways that link diabetes and high extracellular glucose exposure to glomerulosclerosis and mesangial cell extracellular matrix production. However, only in the past ten years has a role for glucose transporters in this process been addressed. Many different glucose transporters are expressed in glomeruli; of these, the GLUT1 facilitative glucose transporter is upregulated in the diabetic renal cortex and in response to glomerular hypertension, as well as in cultured mesangial cells exposed to high glucose. Transgenic mouse and cell models have recently been developed to test the role of GLUT1 in the pathogenesis of glomerulosclerosis with and without diabetes. Clinical studies of GLUT1 alleles performed in humans have identified GLUT1 susceptibility alleles for diabetic nephropathy. Studies are also currently under way to assess the potential role of GLUT1 in nondiabetic renal disorders. 相似文献
36.
Background
Alcoholism presents widespread social and human health problems. Alcohol sensitivity, the development of tolerance to alcohol and susceptibility to addiction vary in the population. Genetic factors that predispose to alcoholism remain largely unknown due to extensive genetic and environmental variation in human populations. Drosophila, however, allows studies on genetically identical individuals in controlled environments. Although addiction to alcohol has not been demonstrated in Drosophila, flies show responses to alcohol exposure that resemble human intoxication, including hyperactivity, loss of postural control, sedation, and exposure-dependent development of tolerance. 相似文献37.
J. Peter Brosius 《Human ecology: an interdisciplinary journal》1991,19(2):123-150
Bailey et al. (1989) and Headland (1987) have recently proposed hypotheses stating that human foragers are unable to live in undisturbed tropical rain forests without some reliance on cultivated foods. The present discussion considers these hypotheses, as well as some of the evidence by which they have been tested. Four conceptual problems in the way these hypotheses have been formulated are identified: (1) assumptions about the relationship between key features of tropical forest ecosystems and human subsistence potential, (2) in-consistencies in the definition of pure foraging, (3) adherence to a dichotomy between foraging and agriculture, the result being that conscious and unconscious effects of exploitation on the demographic parameters of key resources is ignored, and (4) problems in defining the significance of ecotones. I consider the case of Penan hunter-gatherers of Borneo, a population which, by virtue of their reliance on the sago palm Eugeissona utilis, contradicts the conclusions of Bailey et al. and Headland. I consider salient aspects of Penan reliance on Eugeissona, and describe how Penan exploitation of this resource may positively effect its availability. This case is seen to provide a challenge to the hypotheses of Bailey et al. and Headland, not only in the extent to which it contradicts their conclusions but, more significantly, in what it reveals about the assumptions upon which their hypotheses are based. This points to the need for greater precision in the definition of future hypotheses about foraging in tropical forests. 相似文献
38.
Scott A. Beers Elizabeth A. Malloy Wei Wu Michael P. Wachter Uma Gunnia Druie Cavender Crafford Harris Janet Davis Ruth Brosius J.Lee Pellegrino-Gensey John Siekierka 《Bioorganic & medicinal chemistry》1997,5(12):2203-2211
A series of nitroarylhydroxymethylphosphonic acids was synthesized and evaluated as inhibitors of CD45. It was discovered that both the alpha hydroxy and nitro groups are essential for activity. Potency is enhanced by the addition of a large lipophilic group on the aryl ring adjacent to the phosphonic acid moiety. Kinetics studies have shown that these compounds are competitive inhibitors and thus bind at the active site of this enzyme 相似文献
39.
The contribution of RNAs and retroposition to evolutionary novelties 总被引:13,自引:0,他引:13
Brosius J 《Genetica》2003,118(2-3):99-115
40.
The characterization of mutant Bacillus subtilis adenylosuccinate lyases corresponding to severe human adenylosuccinate lyase deficiencies 下载免费PDF全文
Palenchar JB Crocco JM Colman RF 《Protein science : a publication of the Protein Society》2003,12(8):1694-1705
Adenylosuccinate lyase is a homotetramer that catalyzes two discrete reactions in the de novo synthesis of purines: the cleavage of adenylosuccinate and succinylaminoimidazole carboxamide ribotide (SAICAR). Several point mutations in the gene encoding the enzyme have been implicated in human disease. Bacillus subtilis adenylosuccinate lyase was used as a model system in which mutations were constructed corresponding to those mutations associated with severe human adenylosuccinate lyase deficiency. Site-directed mutagenesis was utilized to construct amino acid substitutions in B. subtilis adenylosuccinate lyase; Met(10), Ile(123), and Thr(367) were replaced by Leu, Trp, and Arg, respectively, and the altered enzymes were expressed in Escherichia coli. These purified enzymes containing amino acid substitutions were found to have substantial catalytic activity and exhibit relatively small changes in their kinetic parameters. The major deviations from the wild-type-like behavior were observed upon biophysical characterization. All of these enzymes with amino acid replacements are associated with marked thermal instability. I123W adenylosuccinate lyase exhibits notable changes in the circular dichroism spectra, and a native gel electrophoresis pattern indicative of some protein aggregation. T367R also exhibits alterations at the quarternary level, as reflected in native gel electrophoresis. Experimental results, combined with homology modeling, suggest that the altered enzymes are primarily structurally impaired. The enzyme instability was found to be lessened by subunit complementation with the wild-type enzyme, under mild conditions; these studies may have implications for the in vivo behavior of adenylosuccinate lyase in heterozygous patients. Residues Met(10), Ile(123), and Thr(367) appear to be located in regions of the enzyme important for maintaining the structural integrity required for a stable, functional enzyme. 相似文献