全文获取类型
收费全文 | 884篇 |
免费 | 11篇 |
国内免费 | 43篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 9篇 |
2019年 | 13篇 |
2018年 | 12篇 |
2017年 | 11篇 |
2016年 | 14篇 |
2015年 | 43篇 |
2014年 | 35篇 |
2013年 | 38篇 |
2012年 | 33篇 |
2011年 | 35篇 |
2010年 | 28篇 |
2009年 | 133篇 |
2008年 | 136篇 |
2007年 | 83篇 |
2006年 | 52篇 |
2005年 | 44篇 |
2004年 | 25篇 |
2003年 | 18篇 |
2002年 | 22篇 |
2001年 | 23篇 |
2000年 | 23篇 |
1999年 | 34篇 |
1998年 | 25篇 |
1997年 | 17篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1993年 | 2篇 |
排序方式: 共有938条查询结果,搜索用时 343 毫秒
901.
We present a Bayesian method for the reconstruction of pedigrees in clonal populations using co-dominant genomic markers such as microsatellites and single nucleotide polymorphisms (SNPs). The accuracy of the algorithm is demonstrated for simulated data. We show that the joint estimation of parameters of interest such as the rate of self-fertilization is possible with high accuracy even with marker panels of moderate power. Classical methods can only assign a very limited number of statistically significant parentages in this case and would therefore fail. Statistical confidence is estimated by Markov Chain Monte Carlo (MCMC) sampling. The method is implemented in a fast and easy to use open source software that scales to large datasets with many thousand individuals. 相似文献
902.
Yoshihide Takaki Takayuki Kawahara Hisashi Kitamura Ko-ichi Endo Takuma Kudo 《Conservation Genetics》2009,10(2):269-279
Japanese goshawk was classified as a vulnerable species in the Red Data Book. There have been possibilities of a decrease
of genetic diversity accompanied by habitat loss and genetic pollution due to hybridization with escaping imported goshawks.
In this paper, genetic diversity, gene flow and conservation of Northern Goshawk (Accipiter gentilis) in Japan are discussed and compared with that in Central Asia. We used 11 newly developed microsatellite markers and also
adopted six previously published markers. Genetic diversity was shown to be maintained with 0.58 as mean heterozygosity and
3.95 as mean allelic richness. The degree of genetic differentiation across all populations was low (Nei’s genetic differentiation
index = 0.036, Wright’s genetic differentiation index = 0.039), possibly due to gene flow via adjacent regions (average number
of migrants = 4.26; 0.68–20.30). However, it is possible that slight differentiation resulted from the short divergence time
and/or inflow of escaping imported individuals. We recommend that goshawks in eastern Japan should be managed as a single
unit. They do not appear to be under threat genetically at present, but there is the potential for rapid loss of genetic diversity.
For future conservation, investigations of dispersal routes and actual conditions of gene flow are also recommended. To prevent
further inflow of escaping goshawks into natural populations, it is desirable to reduce importation of goshawks and to enact
a regulation obliging purchasers to register imported goshawks.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
903.
Paula K. Lehtonen Anni Tonteri Dmitri Sendek Sergey Titov Craig R. Primmer 《Conservation Genetics》2009,10(2):281-289
The brown trout populations of the Baltic Sea region have been drastically affected by various human activities during the
past century. Due to their propensity to home to their natal site to spawn and their tendency to evolve local adaptations,
populations may be genetically differentiated in water systems where no physical barriers preventing interbreeding exist.
Consequently, identification of management units, a prerequisite for appropriate conservation and management planning, cannot
necessarily be deduced from the physical properties of the habitat. In this study, microsatellite markers were employed to
assess the spatio-temporal genetic structuring of inter-connected brown trout populations from a river-system in Northwest
Russia. Populations were found to be genetically differentiated from each other (global F
ST 0.06) and the genetic structuring within the river to follow an isolation by distance pattern. Indications of temporal stability
were found in some populations, however others appeared to be temporally unstable suggesting differences in the demographic
forces affecting the populations. Based on the observed isolation by distance pattern of genetic differentiation, preserving
several breeding sites spaced evenly throughout the river-system would appear to be more appropriate than focussing conservation
effort on any single stretch of the river.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
904.
《DNA Repair》2016
DNA mismatch repair (MMR) is a surveillance mechanism present in most living organisms, which repairs errors introduced by DNA polymerases. Importantly, loss of MMR function due to inactivating mutations and/or epigenetic silencing results in the accumulation of mutations and as consequence increased cancer susceptibility, as observed in Lynch syndrome patients.During the past decades important progress has been made in the MMR field resulting in the identification and characterization of essential MMR components, culminating in the in vitro reconstitution of 5′ and 3′ nick-directed MMR. However, several mechanistic aspects of the MMR reaction remain not fully understood, therefore alternative approaches and further investigations are needed.Recently, the use of imaging techniques and, more specifically, visualization of MMR components in living cells, has broadened our mechanistic understanding of the repair reaction providing more detailed information about the spatio-temporal organization of MMR in vivo. In this review we would like to comment on mechanistic aspects of the MMR reaction in light of these and other recent findings. Moreover, we will discuss the current limitations and provide future perspectives regarding imaging of mismatch repair components in diverse organisms. 相似文献
905.
The green mussel, Perna viridis is ecologically and economically important in the coastal region of the South China Sea. Determining its population genetic structure at this fine geographic scale will help sustainable management of natural stocks. In this study, we examined the genetic diversity and population genetic structure of P. viridis from four locations in the South China Sea (n = 45–48) using nine microsatellite loci. The results showed moderate levels of genetic diversity in all four samples (mean A = 13.222–14.000, mean Ae = 7.092–7.571, mean Ar = 12.894–13.746, mean Ho = 0.596–0.656, mean He = 0.690–0.733) and a large effective population size estimate for the pooled sample (total Ne estimates = infinity, 95% CI = 1869.0-infinity). We did not detect any sign of recent bottleneck events in P. viridis populations in the South China Sea. The conventional and a model-based analysis reveal low, non-significant genetic divergence among the four samples (FST = − 0.001–0.005, P > 0.05/6). The results obtained from this study can provide valuable genetic information for the conservation and fishery management of P. viridis by retaining the high Ne estimates. 相似文献
906.
907.
908.
Sinojackia huangmeiensis is a critically endangered tree species in the Styracaceae endemic to China. To create tools to better evaluate the genetic diversity of this species, we used a modified genomic library enrichment method, the PETUER (Probe Extension and TEACl Universal EnRichment) method, to develop genetic markers. The resulting 18 microsatellite loci had high polymorphism with 3–12 alleles per locus and showed negligible stutter. Observed (HO) heterozygosities were 0.057–0.724, and polymorphism information content (PIC) was 0.109–0.794. No significant linkage disequilibrium between pairs of loci was found. All 123 individuals found in the National Natural Reserve of Longgan Lake was genotyped at the 18 loci and used to estimate a UPGMA dendrogram. Using an iterative clustering method, a set of 18 individuals was established as a core collection to represent genetic diversity and would be useful to facilitate the conservation for S. huangmeiensis. In addition, we tested the 18 loci for cross-species amplification in three other Sinojackia species and the closely related Changiostyrax dolichocarpa. These polymorphic loci will be valuable for future population genetic and phylogenetic studies of S. huangmeiensis and congeneric species, as well as in closely related Styracaceae. 相似文献
909.
Reina Uno Mami Kondo Takashi Yuasa Kiyoshi Yamauchi Hihumi Tsuruga Hidetoshi B. Tamate Masaaki Yoneda 《Population Ecology》2012,54(4):509-519
Non-invasive DNA genotyping using hair samples has become a common method in population surveys of Asiatic black bears (Ursus thibetanus) in Japan; however, the accuracy of the genotyping data has rarely been discussed in empirical studies. Therefore, we conducted a large-scale pilot study to examine genotyping accuracy and sought an efficient way of error-checking hair-trapping data. We collected 2,067 hair samples, successfully determined the genotypes of 1,245 samples, and identified 295 individuals. The genotyping data were further divided into 3 subsets of data according to the number of hairs used for DNA extraction in each sample (1–4, 5–9, and ≥10 hairs), and the error rates of allelic dropout and false alleles were estimated for each subset using a maximum likelihood method. The genotyping error rates in the samples with ≥10 hairs were found to be lower than those in the samples with 1–4 and 5–9 hairs. The presence of erroneous genotypes among the identified individuals was further checked using a post hoc goodness-of-fit test that determined the match between the expected and observed frequencies of individual homozygotes at 0–6 loci. The results indicated the presence of erroneous genotypes, possibly as a result of allelic dropout, in the samples. Therefore, for improved accuracy, it is recommended that samples containing ≥10 hairs should be used for genotyping and a post hoc goodness-of-fit test should be performed to exclude erroneous genotypes before proceeding with downstream analysis such as capture-mark-recapture estimation. 相似文献
910.