全文获取类型
收费全文 | 132篇 |
免费 | 7篇 |
出版年
2022年 | 1篇 |
2021年 | 5篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 7篇 |
2013年 | 6篇 |
2012年 | 8篇 |
2011年 | 9篇 |
2010年 | 7篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2005年 | 2篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1969年 | 4篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1957年 | 1篇 |
1946年 | 1篇 |
1942年 | 1篇 |
1937年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有139条查询结果,搜索用时 15 毫秒
1.
High pressure liquid chromatography of cyclic nucleotide phosphodiesterase from purified human T-lymphocytes 总被引:3,自引:0,他引:3
S A Robicsek J J Krzanowski A Szentivanyi J B Polson 《Biochemical and biophysical research communications》1989,163(1):554-560
The cyclic nucleotide phosphodiesterase (EC 3.1.4.17) in extracts of purified human peripheral blood T-lymphocytes was examined by ion exchange high pressure liquid chromatography. Four peaks of activity were isolated. The first peak of activity selectively hydrolyzed cyclic GMP. The following 3 peaks of activity (Ia, IIa and IIIa) were selective for cyclic AMP. The selective low Km cyclic AMP-phosphodiesterase inhibitor, Ro 20-1724 (d,1-1,4-[3-butoxy-4-methoxybenzyl]-2-imidazolidinone), did not inhibit the activity in Ia whereas it did inhibit the activity in IIa and IIIa (IC50 = 17 microM). The authors conclude that ion exchange high pressure liquid chromatography described in this communication is a useful method for the isolation of different forms of cyclic nucleotide phosphodiesterase activity from human T-lymphocytes. 相似文献
2.
3.
4.
5.
Litman GW; Rast JP; Shamblott MJ; Haire RN; Hulst M; Roess W; Litman RT; Hinds- Frey KR; Zilch A; Amemiya CT 《Molecular biology and evolution》1993,10(1):60-72
Immunoglobulins are encoded by a large multigene system that undergoes
somatic rearrangement and additional genetic change during the development
of immunoglobulin-producing cells. Inducible antibody and antibody-like
responses are found in all vertebrates. However, immunoglobulin possessing
disulfide-bonded heavy and light chains and domain-type organization has
been described only in representatives of the jawed vertebrates. High
degrees of nucleotide and predicted amino acid sequence identity are
evident when the segmental elements that constitute the immunoglobulin gene
loci in phylogenetically divergent vertebrates are compared. However, the
organization of gene loci and the manner in which the independent elements
recombine (and diversify) vary markedly among different taxa. One striking
pattern of gene organization is the "cluster type" that appears to be
restricted to the chondrichthyes (cartilaginous fishes) and limits
segmental rearrangement to closely linked elements. This type of gene
organization is associated with both heavy- and light-chain gene loci. In
some cases, the clusters are "joined" or "partially joined" in the germ
line, in effect predetermining or partially predetermining, respectively,
the encoded specificities (the assumption being that these are expressed)
of the individual loci. By relating the sequences of transcribed gene
products to their respective germ-line genes, it is evident that, in some
cases, joined-type genes are expressed. This raises a question about the
existence and/or nature of allelic exclusion in these species. The
extensive variation in gene organization found throughout the vertebrate
species may relate directly to the role of intersegmental
(V<==>D<==>J) distances in the commitment of the individual
antibody-producing cell to a particular genetic specificity. Thus, the
evolution of this locus, perhaps more so than that of others, may reflect
the interrelationships between genetic organization and function.
相似文献
6.
Granulated agarose gels suitable for gel exclusion chromatography of proteins of any molecular weight may now be prepared. This was made possible by the observation that agarose solutions of 16% polysaccharide may be prepared by displacing 8% agarose from solution with 8% polyethylene glycol Mr 6000. The displaced polysaccharide concentrates in a viscous mass occupying half the volume of the original carbohydrate solution. By diluting the displaced polysaccharide with hot watery solutions of electrolyte and allowing the solutions to congeal, gels of any desired concentration, ranging from low to the maximum of 16%, may be prepared. 相似文献
7.
A Polson 《Preparative biochemistry》1977,7(2):129-154
The displacement action of polyethylene glycol of different molecular weights may be linked to the ability of the polymers to form coiled particles in solution. From conclusions drawn from their sedimentating properties in centrifugal fields the polyethylene glycols of low molecular weights, as expected, are less randomly coiled than those of higher molecular weight. It is suggested that protein molecules have the ability to diffuse into the coils of the polyethylene glycol from which they are excluded when the random coiling increases with increasing polymer concentration. From considerations based on the interaction of the polymer filament with the displaced particle the distribution of the substance between the coils and the intermolecular spaces may be predicted semi-quantitatively. 相似文献
8.
9.
Wallace OB Smith DW Deshpande MS Polson C Felsenstein KM 《Bioorganic & medicinal chemistry letters》2003,13(6):1203-1206
Inhibitors of amyloid-beta (Abeta) protein production have been widely pursued as a potential treatment for Alzheimer's disease. Following the identification of a 5 microM screening hit, SAR was initiated using solid-phase synthetic techniques. Two series of alpha-hydroxy esters and ketones which are sub-micromolar inhibitors of Abeta production were identified. The most potent alpha-hydroxyketone identified is approximately 30-fold more potent than the initial lead. 相似文献
10.
Olendzenski L Liu L Zhaxybayeva O Murphey R Shin DG Gogarten JP 《Journal of molecular evolution》2000,51(6):587-599
Members of the Deinococcaceae (e.g., Thermus, Meiothermus, Deinococcus) contain A/V-ATPases typically found in Archaea or Eukaryotes which were probably acquired by horizontal gene transfer. Two methods were used to quantify the extent to which archaeal or eukaryotic genes have been acquired by this lineage. Screening of a Meiothermus ruber library with probes made against Thermoplasma acidophilum DNA yielded a number of clones which hybridized more strongly than background. One of these contained the prolyl tRNA synthetase (RS) gene. Phylogenetic analysis shows the M. ruber and D. radiodurans prolyl RS to be more closely related to archaeal and eukaryal forms of this gene than to the typical bacterial type. Using a bioinformatics approach, putative open reading frames (ORFs) from the prerelease version of the D. radiodurans genome were screened for genes more closely related to archaeal or eukaryotic genes. Putative ORFs were searched against representative genomes from each of the three domains using automated BLAST. ORFs showing the highest matches against archaeal and eukaryotic genes were collected and ranked. Among the top-ranked hits were the A/V-ATPase catalytic and noncatalytic subunits and the prolyl RS genes. Using phylogenetic methods, ORFs were analyzed and trees assessed for evidence of horizontal gene transfer. Of the 45 genes examined, 20 showed topologies in which D. radiodurans homologues clearly group with eukaryotic or archaeal homologues, and 17 additional trees were found to show probable evidence of horizontal gene transfer. Compared to the total number of ORFs in the genome, those that can be identified as having been acquired from Archaea or Eukaryotes are relatively few (approximately 1%), suggesting that interdomain transfer is rare. 相似文献