全文获取类型
收费全文 | 210篇 |
免费 | 28篇 |
国内免费 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 4篇 |
2015年 | 11篇 |
2014年 | 8篇 |
2013年 | 7篇 |
2012年 | 13篇 |
2011年 | 10篇 |
2010年 | 8篇 |
2009年 | 12篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 3篇 |
2004年 | 10篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 4篇 |
1999年 | 6篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1973年 | 3篇 |
1969年 | 2篇 |
1959年 | 1篇 |
1958年 | 3篇 |
1932年 | 1篇 |
1920年 | 1篇 |
1919年 | 1篇 |
1918年 | 2篇 |
1917年 | 1篇 |
1915年 | 1篇 |
1911年 | 3篇 |
1904年 | 1篇 |
排序方式: 共有239条查询结果,搜索用时 15 毫秒
1.
Distribution and fetomaternal transfer of 6 beta-hydroxycortisol (6 beta-OHF) was studied using serial sampling following injection of tritium labelled 6 beta-OHF into various fluid compartments in the chronically cannulated unaesthesized pregnant ewe. There was a rapid transfer of 6 beta-OHF from the fetal circulation into amniotic fluid and maternal blood. In contrast, the maternal----fetal transfer of this steroid metabolite was considerably less. The sequence of appearance of 6 beta-OHF in fetal blood and amniotic fluid following injection into maternal blood suggests that this steroid is first transferred across the placenta to fetal blood before gaining entry into the amniotic fluid space. The half-lives of 6 beta-OHF after initial equilibration in maternal plasma, fetal plasma and amniotic fluid were 2.0 h, 5.1 h and 8.9 h respectively. The amniotic sac appears to contain a relatively static pool of 6 beta-OHF and may act as a "trap" for 6 beta-OHF in the ovine conceptus. 相似文献
2.
3.
Molecular characterization of the marker chromosome associated with cat eye syndrome. 总被引:8,自引:2,他引:6
A. J. Mears A. M. Duncan M. L. Budarf B. S. Emanuel B. Sellinger J. Siegel-Bartelt C. R. Greenberg H. E. McDermid 《American journal of human genetics》1994,55(1):134-142
Cat eye syndrome (CES) is associated with a supernumerary bisatellited marker chromosome which is derived from duplicated regions of 22pter-22q11.2. In this study we have used dosage and RFLP analyses on 10 CES patients with marker chromosomes, by using probes to five loci mapped to 22q11.2. The sequences recognized by the probes D22S9, D22S43, and D22S57 are in four copies in all patients, but the sequences at the more distal loci, D22S36 and D22S75, are duplicated only in some individuals. D22S36 is present in three copies in some individuals, and D22S75 is present in two copies in the majority of cases. Only three individuals have a duplication of the most distal locus examined (D22S75), and these individuals have the largest marker chromosomes identified in this study. From the dosage analysis it was found that the marker chromosomes are variable in size and can be asymmetric in nature. There is no obvious correlation between the severity of the phenotype and the size of the duplication. The distal boundary of the CES critical region (D22S36) is proximal to that of DiGeorge syndrome, a contiguous-gene-deletion syndrome of 22q11.2. 相似文献
4.
Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews
(genus Sorex) for the region between the tRNA(Pro) and the conserved
sequence block-F revealed variable numbers of 79-bp tandem repeats. These
repeats were found in all 19 individuals sequenced, representing three
subspecies and one closely related species of the masked shrew group (Sorex
cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an
outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an
adjacent 76-bp imperfect copy of the tandem repeats. One individual was
heteroplasmic for length variants consisting of five and seven copies of
the 79-bp tandem repeat. The sequence of the repeats is conducive to the
formation of secondary structure. A termination-associated sequence is
present in each of the repeats and in a unique sequence region 5' to the
tandem array as well. Mean genetic distance between the masked shrew taxa
and the pygmy shrew was calculated separately for the unique sequence
region, one of the tandem repeats, the imperfect repeat, and these three
regions combined. The unique sequence region evolved more rapidly than the
tandem repeats or the imperfect repeat. The small genetic distance between
pairs of tandem repeats within an individual is consistent with a model of
concerted evolution. Repeats are apparently duplicated and lost at a high
rate, which tends to homogenize the tandem array. The rate of D- loop
sequence divergence between the masked and pygmy shrews is estimated to be
15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid
sequence evolution in shrews may be due either to their high metabolic rate
and short generation time or to the presence of variable numbers of tandem
repeats.
相似文献
5.
6.
大鼠胼胝体内神经肽Y免疫反应阳性纤维的发育 总被引:1,自引:0,他引:1
本实验用免疫组织化学ABC法研究了大鼠胼胝体内神经肽Y免疫反应阳性(NPY-IR)纤维的生后发育。结果发现,许多NPY-IR纤维在大鼠出生时便存在于胼胝体内。NPY-IR胼胝体纤维的密度在生后1周内继续逐渐增高,在第2周内达到最高峰。之后,NPY-IR胼胝体纤维的密度逐渐下降,至第3周末时接近成年时的水平,即仅有少量NPY-IR纤维存在于胼胝体内。这些结果提示在大鼠早期生后发育过程中许多NPY-IR胼胝体纤维是暂时性的,其作用可能与大脑皮质的机能发育有关。 相似文献
7.
Minute supernumerary ring chromosome 22 associated with cat eye syndrome: further delineation of the critical region. 总被引:3,自引:1,他引:2
下载免费PDF全文
![点击此处可从《American journal of human genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A J Mears H el-Shanti J C Murray H E McDermid S R Patil 《American journal of human genetics》1995,57(3):667-673
Cat eye syndrome (CES) is typically associated with a supernumerary bisatellited marker chromosome (inv dup 22pter-22q11.2) resulting in four copies of this region. We describe an individual showing the inheritance of a minute supernumerary double ring chromosome 22, which resulted in expression of all cardinal features of CES. The size of the ring was determined by DNA dosage analysis and FISH analysis for five loci mapping to 22q11.2. The probes to the loci D22S9, D22S43, and ATP6E were present in four copies, whereas D22S57 and D22S181 were present in two copies. This finding further delineates the distal boundary of the critical region of CES, with ATP6E being the most distal duplicated locus identified. The phenotypically normal father and grandfather of the patient each had a small supernumerary ring chromosome and demonstrated three copies for the loci D22S9, D22S43, and ATP6E. Although three copies of this region have been reported in other cases with CES features, it is possible that the presence of four copies leads to greater susceptibility. 相似文献
8.
Francesco Ramirez J. Gregory Mears Arthur Bank 《Molecular and cellular biochemistry》1980,31(1):133-145
Summary The structure and organization of the human globin genes at the nucleotide level has been established by restriction endonuclease digestion of cellular DNA, and by the isolation and purification of these. genes in phage vectors. With this approach it has been possible to define alterations at the DNA level resulting in a group of inherited diseases of man known as the thalassemia syndromes, and related disorders. Combined with other known genetic and biochemical data, these studies provide a framework for understanding the pathogenesis of these disorders at the molecular level. 相似文献
9.
10.