全文获取类型
收费全文 | 186篇 |
免费 | 4篇 |
出版年
2022年 | 1篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2012年 | 6篇 |
2011年 | 18篇 |
2010年 | 5篇 |
2009年 | 2篇 |
2008年 | 11篇 |
2007年 | 5篇 |
2006年 | 11篇 |
2005年 | 3篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 5篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1968年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有190条查询结果,搜索用时 15 毫秒
1.
Data on immuno- and biochemical identification, genetic control and phylogenesis of new allotype Lpm13 of the Lpm system in domestic mink are presented. This allotype is encountered in mink populations with the frequency 0.9 and higher. The availability of Lpm13 genetic marker permitted another haplotype to be revealed, in addition to the eight known Lpm haplotypes by means of genetic analysis. It was established that, alongside with the earlier described haplotype Lpm3,4,6,8,9,10,11 (abbreviation H3), there exists a similar haplotype, Lpm3,4,6,8,9,10,11,13 (abbreviation H3.13), containing the Lpm13 gene. Of the rest seven haplotypes, five have the Lpm13 gene and two do not. Taking into account this gene and corresponding antigenic marker, the differentiation of 28, instead of 25, phenotypes and 45, instead of 36, genotypes for the Lpm system became possible. Lpm13 antigenic specificity was found with no exception in all individual serum samples taken from ten species and interspecific hybrids of Mustelidae which are closely related to domestic mink. The data obtained give grounds to refer the newly identified Lpm13 gene to the first evolutionary conservative category of genes of the multigenic Lpm system which is also represented by the Lpm6, Lpm9, Lpm10 and Lpm11 genes. The hypotheses of instantaneous formation of polymorphism of the Lpm system in domestic mink are briefly regarded. 相似文献
2.
Borrelia burgdorferi is a spirochete pathogen transmitted among warm-
blooded hosts by ixodid ticks. Frequency-dependent selection for variant
outer-surface proteins might be expected to arise in this species, since
rare variants are more likely to avoid immune surveillance in previously
infected hosts. We sequenced the OspA and OspB genes of nine North American
strains and compared them with nine strains previously described. For each
gene, the mean number of synonymous substitutions per synonymous site and
the mean number of nonsynonymous substitutions per nonsynonymous site show
only a twofold excess of silent mutations. Synonymous rates vary widely
along the OspB protein. Some regions show a significant excess of silent
substitutions, while divergence in other regions is constrained by biased
base composition or selection. The presence, in antigenically important
regions of the protein, of significant variation among strains, as well as
evidence for recombination among strains, should be considered in attempts
to develop vaccines against this disease.
相似文献
3.
Igor A. Skulskii Margarita V. Savina Vadim V. Glasunov Nils-Erik L. Saris 《The Journal of membrane biology》1978,44(2):187-194
Summary The distribution of Tl+ between rat liver mitochondria and the medium was studied; millimolar or smaller concentrations of Tl+ were labeled with204Tl. The Tl+ distribution responded to transient diffusion potentials in a way that indicated electrophoretic movements of Tl+. The diffusion potentials were induced by efflux of K+ in response to addition of valinomycin to nonrespiring mitochondria suspended in a medium with low concentrations of K+ or by efflux of H+ induced by making the medium more alkaline in the presence of a protonophorous (proton-conducting) uncoupling agent. Changes in membrane potential induced by valinomycin were followed with the aid of safranine. Tl+ brought about collapse of the diffusion potential. It is concluded that Tl+ is able to penetrate the mitochondrial membrane electrophoretically. 相似文献
4.
Mink Ld1 antigen of serum low-density lipoprotein was demonstrated by alloantibodies. No genetic relation was found between Ld1 and the Lpm system of very-high-density lipoprotein. The existence of an autosomal dominant gene, coding for the new alloantigenic marker, is postulated on the basis of mink breeding data. 相似文献
5.
Ld1, an antigen of serum low density lipoprotein, was identified by means of mink alloimmunization. No genetic relation was established between Ld1 and the Ipm-system of very high density lipoprotein. Based on the analysis of breeding data, the existence of an autosomal dominant gene, Ld1+, is postulated. This gene codes for the new alloantigenic marker. The existence of at least one other allotype of the Ld-system is suggested. 相似文献
6.
Three new allotypes were discovered in mink sera by means of isoimmunization. Based on the results of identifications, they were referred to the Lpm system of serum alpha2-lipoprotein. They were designated as Lpm 6, Lpm 7 and Lpm 8. The allotyping of serum samples from 342 minks made possible to establish a relation between Lpm 7 and Lpm 8 using the chi2 method; it was also found that these two allotypes related to each of the first five Lpm as well as to their phenotypes, which was described earlier. There was a significant dependence of the expression of Lpm 6 on Lpm 5 indicating a genetic relation between Lpm 6 and other allotypes. The detection of Lpm 6, 7 and 8, which are the most likely under the control of the same gene (or a sustem of genes) as Lpm 1, 2, 3 and 5, is an evidence for the complex structure of the Lpm locus. 相似文献
7.
1. High efficiency of oxidative phosphorylation and a good respiratory control in liver, heart and somatic muscle mitochondria of the lamprey (Lampetra fluviatilis) were observed when the particles were isolated in a complex sucrose medium containing EDTA, heparin and nicotinamide. The coupling properties of these mitochondria were further improved by including serum albumin in the incubation medium. 2. The content of total adenine nucleotides in lamprey mitochondria was between 4 and 6 nmoles/mg protein. The translocation of these nucleotides across mitochondrial membrane was stimulated by serum albumin. 3. Lamprey mitochondrial phospholipids contain a large proportion (64-72%) of polyunsaturated fatty acids. 4. Electron micrographs of mitochondria from lamprey liver, heart and somatic muscle are presented. 相似文献
8.
We have used an end-to-end ecosystem model to explore responses over 30 years to coastal no-take reserves covering up to 6% of the fifty thousand square kilometres of continental shelf and slope off the coast of New South Wales (Australia). The model is based on the Atlantis framework, which includes a deterministic, spatially resolved three-dimensional biophysical model that tracks nutrient flows through key biological groups, as well as extraction by a range of fisheries. The model results support previous empirical studies in finding clear benefits of reserves to top predators such as sharks and rays throughout the region, while also showing how many of their major prey groups (including commercial species) experienced significant declines. It was found that the net impact of marine reserves was dependent on the pre-existing levels of disturbance (i.e. fishing pressure), and to a lesser extent on the size of the marine reserves. The high fishing scenario resulted in a strongly perturbed system, where the introduction of marine reserves had clear and mostly direct effects on biomass and functional biodiversity. However, under the lower fishing pressure scenario, the introduction of marine reserves caused both direct positive effects, mainly on shark groups, and indirect negative effects through trophic cascades. Our study illustrates the need to carefully align the design and implementation of marine reserves with policy and management objectives. Trade-offs may exist not only between fisheries and conservation objectives, but also among conservation objectives. 相似文献
9.
Nesterenko VS Iatsenko EM Savina NP Khakaiu IL 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2004,44(5):560-562
In experiments with Wistar rats exposed to 7.5 Gy, polycationic sorbent ICHANT with gel structure and pores of various size exhibited stronger antitoxic properties as compared to carbon sorbents. 相似文献
10.