全文获取类型
收费全文 | 505篇 |
免费 | 62篇 |
出版年
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 18篇 |
2014年 | 17篇 |
2013年 | 28篇 |
2012年 | 21篇 |
2011年 | 21篇 |
2010年 | 30篇 |
2009年 | 27篇 |
2008年 | 24篇 |
2007年 | 17篇 |
2006年 | 15篇 |
2005年 | 25篇 |
2004年 | 13篇 |
2003年 | 9篇 |
2002年 | 14篇 |
2001年 | 12篇 |
2000年 | 10篇 |
1999年 | 4篇 |
1998年 | 13篇 |
1997年 | 14篇 |
1996年 | 4篇 |
1995年 | 14篇 |
1994年 | 6篇 |
1993年 | 10篇 |
1992年 | 4篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 17篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 20篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1978年 | 3篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1975年 | 5篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1970年 | 5篇 |
1969年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有567条查询结果,搜索用时 15 毫秒
11.
Mapping X-linked ophthalmic diseases: II. Linkage relationship of X-linked retinitis pigmentosa to X chromosomal short arm markers 总被引:10,自引:0,他引:10
Summary X-linked retinitis pigmentosa (XLRP) is a series of hereditary dystrophic diseases of the retina that occur in three clinically distinguishable variants: the classic form (McK-31360), a type known as choroidoretinal dystrophy (McK-30330), and a variant with golden-metallic or tapetal reflex in the heterozygote (McK30320). Controversy exists as to whether these phenotypic differences are due to clinical variability in disease expression, heterogeneity in disease alleles at a single locus, or a multiplicity of loci for XLRP. We have studied a single large kindred segregating for XLRP with the metallic fundus reflex in the heterozygote with restriction fragment length polymorphisms (RFLPs) from the short arm of the human X chromosome, and found measurable linkage to DXS7 (=12.5 cMorgans at LOD=2.5), the same RFLP previously shown by others to be tightly linked to the other forms of XLRP at =3cM. Although these estimates appeared to be different, each fell just within the 95% probability interval of the other and, therefore, were insufficient to prove or disprove that the metallic sheen form of XLRP is allelic with other forms of XLRP. Additional RFLPs at the DXS43 and the ornithine transcarbamoylase loci provided three-point crosses for determining the relative positions of DXS7 and XLRP, and supported an order that placed this form of XLRP distal to DXS7 on the Xp. Until the question of genetic heterogeneity is resolved, careful phenotypic characterization of the clinical type of XLRP present in families being used for linkage analyses is advisable.Presented in part at the American Society of Human Genetics meeting, Toronto, Canada, November 1, 1984 相似文献
12.
13.
14.
15.
Linkage analysis of seven kindreds with the X-linked lymphoproliferative syndrome (XLP) confirms that the XLP locus is near DXS42 and DXS37 总被引:5,自引:0,他引:5
James C. Skare Helen L. Grierson John L. Sullivan Robert L. Nussbaum David T. Purtilo Bakary S. Sylla Gilbert M. Lenon Dorothy S. Reilly Bradley N. White Aubrey Milunsky 《Human genetics》1989,82(4):354-358
Summary Analysis of seven kindreds indicates that the XLP locus exhibits 1% recombination with DXS42 (lod = 17.5) and no recombination with DXS37 (lod = 13.3). 相似文献
16.
The phylogeny of Greya Busck (Lepidoptera: Prodoxidae) was inferred from
nucleotide sequence variation across a 765-bp region in the cytochrome
oxidase I and II genes of the mitochondrial genome. Most parsimonious
relationships of 25 haplotypes from 16 Greya species and two outgroup
genera (Tetragma and Prodoxus) showed substantial congruence with the
species relationships indicated by morphological variation. Differences
between mitochondrial and morphological trees were found primarily in the
positions of two species, G. variabilis and G. pectinifera, and in the
branching order of the three major species groups in the genus. Conflicts
between the data sets were examined by comparing levels of homoplasy in
characters supporting alternative hypotheses. The phylogeny of Greya
species suggests that host-plant association at the family level and larval
feeding mode are conservative characters. Transition/transversion ratios
estimated by reconstruction of nucleotide substitutions on the phylogeny
had a range of 2.0-9.3, when different subsets of the phylogeny were used.
The decline of this ratio with the increase in maximum sequence divergence
among taxa indicates that transitions are masked by transversions along
deeper internodes or long branches of the phylogeny. Among transitions,
substitutions of A-->G and T-->C outnumbered their reciprocal
substitutions by 2-6 times, presumably because of the approximately 4:1
(77%) A+T-bias in nucleotide base composition. Of all transversions,
73%-80% were A<-->T substitutions, 85% of which occurred at third
positions of codons; these estimates did not decrease with an increase in
maximum sequence divergence of taxa included in the analysis. The high
frequency of A<-->T substitutions is either a reflection or an
explanation of the 92% A+T bias at third codon positions.
相似文献
17.
18.
19.
Human chromosomal assignments for 14 argininosuccinate synthetase pseudogenes: cloned DNAs as reagents for cytogenetic analysis 总被引:13,自引:6,他引:7
T S Su R L Nussbaum S Airhart D H Ledbetter T Mohandas W E O''Brien A L Beaudet 《American journal of human genetics》1984,36(5):954-964
There are multiple, processed, dispersed pseudogenes for human argininosuccinate synthetase. Chinese hamster X human somatic cell hybrids were used to map DNA fragment groups corresponding to the single expressed gene and 14 pseudogene loci. Each chromosomal assignment was confirmed using hybrids containing very few human chromosomes and/or by demonstrating monosomic or trisomic dosage in human cell lines with chromosomal abnormalities. Pseudogenes were mapped to chromosomes 2cen-p25, 3q12-qter, 4q21-qter, 5 (two loci), 6, 7, 9p13-q11, 9q11-q22, 11q, 12, Xp22-pter, Xq22-q26, and Ycen-q11. DNA fragments from the expressed gene were mapped to 9q34-qter in agreement with the previous assignment for enzyme activity. A high-frequency restriction fragment length polymorphism mapped to 9q11-q22. The analyses emphasized the feasibility of using chromosomally abnormal human cell lines for confirmation and regionalization of gene-mapping assignments made using somatic-cell hybrids. Conversely, cloned DNA probes, once mapped and characterized, can be very valuable for determining the chromosomal composition of interspecies hybrids and the dosage of loci in human cells. The argininosuccinate synthetase cDNA is a convenient reagent for dosage analysis of 15 human loci on 11 different chromosomes. Improved reagents could be designed that would simplify Southern blot patterns by eliminating overlapping DNA fragments and providing a single DNA fragment for each locus. 相似文献
20.
M. Purrello R. Nussbaum A. Rinaldi G. Filippi S. Traccis B. Latte M. Siniscalco 《Human genetics》1984,65(3):295-299
Summary A Sardinian pedigree described in 1964 for having been found to segregate at the X-linked loci for the Xga antigen, G6PD deficiency, Protan and Deutan color blindness, with an instance of recombination between the last two loci, was re-examined with respect to four common X-linked DNA polymorphisms detected by molecular probes homologous to critical subregions of the human X chromosome. Two branches of this pedigree-including the one with the Protan-Deutan recombinant-were found to segregate also for the common BamHI polymorphism identified with the cDNA probe pHPT-2 of the HPRT gene (Xq26). The analysis of the chromosome haplotypes in the male offspring of the phase known penta-heterozygous mother suggests that the probable order of the relevant loci is HPRT, Deutan, G6PD, Protan, Xq telomere. Though we are fully aware of the risks of generalizing the significance of observations made on a single exceptional pedigree, we believe that this report outlines the potential of families of the type described as reasearch tools to resolve the linear order of tightly X-linked loci and to investigate the biology of genetic recombination in humans. 相似文献