全文获取类型
收费全文 | 339篇 |
免费 | 19篇 |
出版年
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 6篇 |
2015年 | 15篇 |
2014年 | 15篇 |
2013年 | 25篇 |
2012年 | 13篇 |
2011年 | 14篇 |
2010年 | 24篇 |
2009年 | 24篇 |
2008年 | 13篇 |
2007年 | 13篇 |
2006年 | 11篇 |
2005年 | 13篇 |
2004年 | 12篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 10篇 |
1997年 | 10篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1991年 | 4篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 1篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 16篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有358条查询结果,搜索用时 15 毫秒
71.
72.
The human factor H-related gene 2 (FHR2): structure and linkage to the coagulation factor XIIIb gene
Christine Skerka Peter F. Zipfel JoAnn M. Moulds Patricia Taillon-Miller Dennis Hourcade 《Immunogenetics》1995,42(4):268-274
The human factor H-related gene 2 (FHR2) encodes a serum protein structurally and immunologically related to complement factor H. We describe the isolation and genomic organization of the human FHR2 gene from a yeast artificial chromosome library. The FHR2 gene is organized in five exosn and span about 7 kilobases (kb) of human genomic DNA. A comparison with the corresponding cDNA sequence (clone DDESK59) shows that the analyzed FHR2 gene has a deleted region within exon 4. A new splice acceptor site created in the truncated exon indicates that the analyzed gene could be translated to a truncated protein. Further, we demonstrate that the genes for FHR2 and subunit of coagulation factor XIII are located in the same 165 kb YAC DNA. Thus, the three structurally related genes FXIIIb, FHR2, and factor H are linked on human chromosome 1 in the regulators of complement activiation (RCA) gene cluster. The physical linkage of the FHR2 and the factor H genes provides additional evidence for a close relatedness of complement factor H and the factor H-related proteins. The linkage and the almost exclusive organization in short consensus repeat-containing domains indicates a close evolutionary relationship of the FXIIIb, FHR2, and factor H genes.The nucleotide sequence data reported in this paper have been submitted to the EMBL and GenBank nucleotide sequence databases and have been assigned the accession number X86564 (exon 1), X86565 (exon 2), X86566 (exon 3 and 4), and X86567 (exon 5) 相似文献
73.
Caccone A; Moriyama EN; Gleason JM; Nigro L; Powell JR 《Molecular biology and evolution》1996,13(9):1224-1232
Drosophila melanogaster belongs to a closely related group of eight species
collectively known as the melanogaster subgroup; all are native to
sub-Saharan Africa and islands off the east coast of Africa. The
phylogenetic relationships of most species in this subgroup have been well
documented; however, the three most closely related species, D. simulans,
D. sechellia, and D. mauritiana, have remained problematic from a
phylogenetic standpoint as no data set has unambiguously resolved them. We
present new DNA sequence data on the nullo and Serendipity-alpha genes and
combine them with all available nuclear DNA sequence data; the total data
encompass 12 genes and the ITS of rDNA. A methodological problem arose
because nine of the genes had information on intraspecific polymorphisms in
at least one species. We explored the effect of inclusion/exclusion of
polymorphic sites and found that it had very little effect on phylogenetic
inferences, due largely to the fact that 82% of polymorphisms are
autapomorphies (unique to one species). We have also reanalyzed our
previous DNA-DNA hybridization data with a bootstrap procedure. The
combined sequence data set and the DNA-DNA hybridization data strongly
support the sister status of the two island species, D. sechellia and D.
mauritiana. This at least partially resolves what had been a paradox of
parallel evolution in these two species.
相似文献
74.
75.
INTRoDUCTIoNlYho1iumrePensL,whiteclover,isaneconomicallyimportantplantspeciesintemperatepastures.Asbrieflyreportedby[1],ithas16pairsofchromosomes(2n=32).Asyet,nodetailedcytologicalexaminationofthisspecies,suchasC-banding,hasbeenrep0rted.Inthelastdecade,thetechnique0fC-bandinghasbeenusedt0examinehighlyrepeatedsequencesinplantchrom0s0mesandhasprovidedausefultoolf0rtheanalysis0fcyt0geneticstructureincr0pplants[2-71.Inplants,thechr0m0s0mall0calizationofhighlyrepeatedDNAsequencesbyinsituhybr… 相似文献
76.
77.
The period (per) locus has received much attention in molecular evolution
studies because it is one of the best studied "behavioral genes" and
because it offers insight into the evolution of repetitive sequences. We
studied most of the coding region of per in Drosophila willistoni and
confirmed previously observed patterns of conservation and divergence among
distantly related species. Five regions are so highly diverged that they
cannot be aligned, whereas a region encompassing the PAS domain is very
conserved. Structural and nucleotide polymorphism patterns in the
willistoni group are not the same as those observed in previously studied
species. We sequenced the region homologous to the highly polymorphic
threonine-glycine repeat of D. melanogaster in multiple strains of D.
willistoni, as well as in other members of willistoni group, and found an
unusual amount of conservation in this region. However, the next
nonconserved region downstream in the sequence is quite variable and
polymorphic for the number of repeated glycines. The glycine codon usage is
significantly different in this glycine repeat as compared to other parts
of the gene. We were able to plot the directionality of change in the
glycine repeat region onto a phylogeny and find that the addition of
glycines is the general trend with the diversification of the willistoni
group.
相似文献
78.
79.
80.
The Dantu erythrocyte phenotype of the NE variety. II. Serology, immunochemistry, genetics, and frequency 总被引:1,自引:0,他引:1
P Unger J L Procter J J Moulds M Moulds D Blanchard M L Guizzo L A McCall J P Cartron W Dahr 《Blut》1987,55(1):33-43
Red cells (RBC) possessing the low-frequency MNSs antigen Dantu from 36 Black individuals (21 propositi) were found to exhibit the NE variety of this phenotype, as judged from the electrophoretic glycophorin (GP) pattern, described in an accompanying article, and/or from the polybrene test which detects the decreased NeuAc level of these RBC. All known DantuNE RBC (53) exhibit the phenotype M+N+. This finding as well as family studies and immunochemical investigations demonstrate that the DantuNE allele encodes a blood group M-specific GP A. Thus, the strongly decreased GP A level of RBC from DantuNE heterozygotes represents the product of the Dantu allele and its normal counterpart. It is suggested that the formation of a complex with the anion channel protein (band 3) represents the prerequisite for optimum incorporation of GP A into normal RBC membranes. The hybrid GP in DantuNE RBC, produced in large quantity, might suppress the incorporation of GP A in a cis and trans manner via the formation of a complex with band 3. The hybrid GP in DantuNE RBC lacks U activity, but expresses N activity and a qualitatively altered s antigen, thus proving its GP B-GP A hybrid nature in conjunction with data described in the accompanying article. Screening of ficin-treated RBC with Vicia lectin revealed that the Dantu phenotype exhibits a frequency of about 0.005 in American Blacks and less than 0.001 in Germans. 相似文献