全文获取类型
收费全文 | 137篇 |
免费 | 10篇 |
出版年
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 11篇 |
2014年 | 10篇 |
2013年 | 11篇 |
2012年 | 5篇 |
2011年 | 8篇 |
2010年 | 10篇 |
2009年 | 8篇 |
2008年 | 11篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有147条查询结果,搜索用时 15 毫秒
101.
Background
Both genome-wide association (GWA) studies and genomic selection depend on the level of non-random association of alleles at different loci, i.e. linkage disequilibrium (LD), across the genome. Therefore, characterizing LD is of fundamental importance to implement both approaches. In this study, using a 60K single nucleotide polymorphism (SNP) panel, we estimated LD and haplotype structure in crossbred broiler chickens and their component pure lines (one male and two female lines) and calculated the consistency of LD between these populations.Results
The average level of LD (measured by r2) between adjacent SNPs across the chicken autosomes studied here ranged from 0.34 to 0.40 in the pure lines but was only 0.24 in the crossbred populations, with 28.4% of adjacent SNP pairs having an r2 higher than 0.3. Compared with the pure lines, the crossbred populations consistently showed a lower level of LD, smaller haploblock sizes and lower haplotype homozygosity on macro-, intermediate and micro-chromosomes. Furthermore, correlations of LD between markers at short distances (0 to 10 kb) were high between crossbred and pure lines (0.83 to 0.94).Conclusions
Our results suggest that using crossbred populations instead of pure lines can be advantageous for high-resolution QTL (quantitative trait loci) mapping in GWA studies and to achieve good persistence of accuracy of genomic breeding values over generations in genomic selection. These results also provide useful information for the design and implementation of GWA studies and genomic selection using crossbred populations.Electronic supplementary material
The online version of this article (doi:10.1186/s12711-015-0098-4) contains supplementary material, which is available to authorized users. 相似文献102.
Nicole Willems Frances C Bach Saskia G M Plomp Mattie HP van Rijen Jeannette Wolfswinkel Guy CM Grinwis Clemens Bos Gustav J Strijkers Wouter JA Dhert Bj?rn P Meij Laura B Creemers Marianna A Tryfonidou 《Arthritis research & therapy》2015,17(1)
IntroductionStrategies for biological repair and regeneration of the intervertebral disc (IVD) by cell and tissue engineering are promising, but few have made it into a clinical setting. Recombinant human bone morphogenetic protein 7 (rhBMP-7) has been shown to stimulate matrix production by IVD cells in vitro and in vivo in animal models of induced IVD degeneration. The aim of this study was to determine the most effective dose of an intradiscal injection of rhBMP-7 in a spontaneous canine IVD degeneration model for translation into clinical application for patients with low back pain.MethodsCanine nucleus pulposus cells (NPCs) were cultured with rhBMP-7 to assess the anabolic effect of rhBMP-7 in vitro, and samples were evaluated for glycosaminoglycan (GAG) and DNA content, histology, and matrix-related gene expression. Three different dosages of rhBMP-7 (2.5 μg, 25 μg, and 250 μg) were injected in vivo into early degenerated IVDs of canines, which were followed up for six months by magnetic resonance imaging (T2-weighted images, T1rho and T2 maps). Post-mortem, the effects of rhBMP-7 were determined by radiography, computed tomography, and macroscopy, and by histological, biochemical (GAG, DNA, and collagen), and biomolecular analyses of IVD tissue.ResultsIn vitro, rhBMP-7 stimulated matrix production of canine NPCs as GAG deposition was enhanced, DNA content was maintained, and gene expression levels of ACAN and COL2A1 were significantly upregulated. Despite the wide dose range of rhBMP-7 (2.5 to 250 μg) administered in vivo, no regenerative effects were observed at the IVD level. Instead, extensive extradiscal bone formation was noticed after intradiscal injection of 25 μg and 250 μg of rhBMP-7.ConclusionsAn intradiscal bolus injection of 2.5 μg, 25 μg, and 250 μg rhBMP-7 showed no regenerative effects in a spontaneous canine IVD degeneration model. In contrast, intradiscal injection of 250 μg rhBMP-7, and to a lesser extent 25 μg rhBMP-7, resulted in extensive extradiscal bone formation, indicating that a bolus injection of rhBMP-7 alone cannot be used for treatment of IVD degeneration in human or canine patients.
Electronic supplementary material
The online version of this article (doi:10.1186/s13075-015-0625-2) contains supplementary material, which is available to authorized users. 相似文献103.
Shui-Lian Yu Paul KS Chan Chun-Kwok Wong Cheuk-Chun Szeto Suzanne C Ho Karine So May MY Yu So-Fan Yim Tak-Hong Cheung Martin CS Wong Jo LK Cheung Apple CM Yeung Edmund K Li Lai-Shan Tam 《Arthritis research & therapy》2012,14(2):R80
IntroductionPrevalence of an abnormal Papanicolaou smear was significantly increased in lupus patients in cross-sectional studies, associated with a higher prevalence of high-risk human papillomavirus (HPV) infection. The nucleic acid-specific Toll-like receptors (TLRs) locate at the endolysosomal compartments and trigger the induction of cytokines for the innate immune response. This study evaluated whether abnormal host innate immune response in lupus patients may enhance HPV persistence.MethodsProtein levels of TLRs 3, 7, 8 and 9 in cervical epithelial cells of lupus patients and controls with or without HPV infection were assessed using flow cytometry. Characteristics associated with the differential expression of TLRs in systemic lupus erythematosus (SLE) were elucidated. The effect and interferon-stimulated genes (ISGs) (ISG15 and Mx-1) gene expressions were then measured in oncogenic HeLa (HPV18), CaSki (HPV) and C33A (HPV negative) cell lines using flow cytometry and quantitative real-time PCR. Ex vivo productions of cytokines and interferon-gamma (IFN-γ) upon TLR ligands stimulations were subsequently measured using cytometric bead array and ELISA.ResultsFor subjects with HPV infection, levels of TLR3 and TLR7 were significantly lower in lupus patients compared with controls. Significantly decreased TLRs 7, 8 and 9 levels were observed in HPV-negative SLE compared to healthy controls. For SLE with and without HPV infection, TLR7 and 9 levels were significantly lower in infected SLE than those in HPV-negative patients. Independent explanatory variables associated with down-regulation of TLR7 level included HPV infection and a higher cumulative dose of prednisolone; while a higher cumulative dose of hydroxychloroquine and HPV infection were associated with down-regulation of TLR9 level. In cervical cell lines, TLRs 3, 7, 8, 9 protein levels and antiviral ISG15 and Mx-1 gene expressions were inhibited in two oncogenic HPV types. Functional data showed that the induction of pro-inflammatory cytokines by TLR ligands (R837, ssRNA and ODN2395) was greatly impaired in CaSki and HeLa than C33A cells.ConclusionsIn conclusion, prednisolone and TLR antagonist (hydroxychloroquine) may down-regulate protein levels of TLR7 and TLR9 in lupus patients, thereby decreasing the innate immune response against HPV infection. Upon infection, HPV further down-regulate TLR7 and 9 levels for viral persistence. Furthermore, reduction of nucleic acid-sensing TLRs 7, 8 and 9 in carcinogenic HPVs ensures that the expression of inducible pro-inflammatory cytokines is minimized to prevent the expression of antiviral ISGs (ISG15 and Mx-1) on a biologically relevant antiviral response. 相似文献
104.
Behnam Abasht Erin Sandford Jesus Arango Petek Settar Janet E Fulton Neil P O'Sullivan Abebe Hassen David Habier Rohan L Fernando Jack CM Dekkers Susan J Lamont 《BMC genomics》2009,10(Z2):S2
Background
The genome sequence and a high-density SNP map are now available for the chicken and can be used to identify genetic markers for use in marker-assisted selection (MAS). Effective MAS requires high linkage disequilibrium (LD) between markers and quantitative trait loci (QTL), and sustained marker-QTL LD over generations. This study used data from a 3,000 SNP panel to assess the level and consistency of LD between single nucleotide polymorphisms (SNPs) over consecutive years in two egg-layer chicken lines, and analyzed one line by two methods (SNP-wise association and genome-wise Bayesian analysis) to identify markers associated with egg-quality and egg-production phenotypes.Results
The LD between markers pairs was high at short distances (r2 > 0.2 at < 2 Mb) and remained high after one generation (correlations of 0.80 to 0.92 at < 5 Mb) in both lines. Single- and 3-SNP regression analyses using a mixed model with SNP as fixed effect resulted in 159 and 76 significant tests (P < 0.01), respectively, across 12 traits. A Bayesian analysis called BayesB, that fits all SNPs simultaneously as random effects and uses model averaging procedures, identified 33 SNPs that were included in the model >20% of the time (φ > 0.2) and an additional ten 3-SNP windows that had a sum of φ greater than 0.35. Generally, SNPs included in the Bayesian model also had a small P-value in the 1-SNP analyses.Conclusion
High LD correlations between markers at short distances across two generations indicate that such markers will retain high LD with linked QTL and be effective for MAS. The different association analysis methods used provided consistent results. Multiple single SNPs and 3-SNP windows were significantly associated with egg-related traits, providing genomic positions of QTL that can be useful for both MAS and to identify causal mutations.105.
106.
Relapsing polychondritis (RP) is an autoimmune disease that affects extra-articular cartilage. Matrilin-1-induced relapsing
polychondritis (MIRP) is a model for RP and is useful for studies of the pathogenic mechanisms in this disease. There are
indications that the major histocompatibility complex (MHC) class II plays a major role in RP, since DR4+ patients are more commonly affected than controls. We have now addressed the role of the MHC region, as well as the non-MHC
contribution, using congenic mouse strains. Of the MHC congenic strains, B10.Q (H2
q
) was the most susceptible, the B10.P (H2
p
) and B10.R (H2
r
) strains developed mild disease, while B10 strains carrying the v, b, f, or u H2 haplotypes were resistant. A slight variation
of susceptibility of H2
q
strains (B10.Q> C3H.Q> DBA/1) was observed and the (B10.Q × DBA/1)F1 was the most susceptible of all strains. Furthermore, macrophages and CD4+ T cells were the most prominent cell types in inflammatory infiltrates of the tracheal cartilage. Macrophages are the major
source of many cytokines, such as interleukin-10 (IL-10), which is currently being tested as a therapeutic agent in several
autoimmune diseases. We therefore investigated B10.Q mice devoid of IL-10 through gene deletion and found that they developed
a significantly more severe disease, with an earlier onset, than their heterozygous littermates. In conclusion, MHC genes,
as well as non-MHC genes, are important for MIRP induction, and IL-10 plays a major suppressive role in cartilage inflammation
of the respiratory tract. 相似文献
107.
The whole-cell patch-clamp technique was used to study the properties of inward ionic currents found in primary cultures of rat and mouse skeletal myotubes and in freshly dissociated fibers of the flexor digitorum brevis muscle of rats. In each of these cell types, test depolarizations from the holding potential (-80 or -90 mV) elicited three distinct inward currents: a sodium current (INa) and two calcium currents. INa was the dominant inward current: under physiological conditions, the maximum inward INa was estimated to be at least 30-fold larger than either of the calcium currents. The two calcium currents have been termed Ifast and Islow, corresponding to their relative rates of activation. Ifast was activated by test depolarizations to around -40 mV and above, peaked in 10-20 ms, and decayed to baseline in 50-100 ms. Islow was activated by depolarizations to approximately 0 mV and above, peaked in 50-150 ms, and decayed little during a 200-ms test pulse. Ifast was inactivated by brief, moderate depolarizations; for a 1-s change in holding potential, half-inactivation occurred at -55 to -45 mV and complete inactivation occurred at -40 to -30 mV. Similar changes in holding potential had no effect on Islow. Islow was, however, inactivated by brief, strong depolarizations (e.g., 0 mV for 2 s) or maintained, moderate depolarizations (e.g., -40 mV for 60 s). Substitution of barium for calcium had little effect on the magnitude or time course of either Ifast or Islow. The same substitution shifted the activation curve for Islow approximately 10 mV in the hyperpolarizing direction without affecting the activation of Ifast. At low concentrations (50 microM), cadmium preferentially blocked Islow compared with Ifast, while at high concentrations (1 mM), it blocked both Ifast and Islow completely. The dihydropyridine calcium channel antagonist (+)-PN 200-110 (1 microM) caused a nearly complete block of Islow without affecting Ifast. At a holding potential of -80 mV, the half-maximal blocking concentration (K0.5) for the block of Islow by (+)-PN 200-110 was 182 nM. At depolarized holding potentials that inactivated Islow by 35-65%, K0.5 decreased to 5.5 nM. 相似文献
108.
Distribution of the molossinus allele of Sry, the testis-determining gene, in wild mice 总被引:3,自引:0,他引:3
Nagamine CM; Shiroishi T; Miyashita N; Tsuchiya K; Ikeda H; Takao N; Wu XL; Jin ML; Wang FS; Kryukov AP 《Molecular biology and evolution》1994,11(6):864-874
When the Y chromosome of the laboratory inbred mouse strain C57BL/6 (B6) is
replaced by the Y of certain strains of Mus musculus domesticus, testis
determination fails and all XY fetuses develop either as hermaphrodites or
XY females (XY sex reversal). This suggests the presence of at least two
alleles of Sry, the male-determining gene on the Y:M. m. domesticus and B6.
The B6 Y chromosome is derived from the Japanese house mouse, M. m.
molossinus and therefore carries a molossinus Sry allele. As a first step
to determine how the molossinus Sry allele evolved, its distribution
pattern was determined in wild mice. The cumulative data of 96 M. musculus
samples obtained from 58 geographical locations in Europe, North Africa,
and Asia show the molossinus Sry allele is restricted to Japan and the
neighboring Asian mainland and confirm that Japanese M. m. molossinus mice
were derived in part from a race of M. m. musculus from Korea or Manchuria.
Sry polymorphisms, as illustrated by the molossinus Sry allele, can serve
as molecular markers for studies on the evolution of wild M. musculus
populations and can help determine the role sex determination plays in
speciation.
相似文献
109.
Members of the ZFY and ZNF6 gene families have been cloned from species
representing different taxa and different modes of sex determination.
Comparisons of these genes show the ZFY-like and ZNF6 sequences to be
strongly conserved across marsupials, birds, and lepidosaurians. Sequence
analyzed by neighbor-joining indicated that both gene families are
monophyletic with a high bootstrap value. Pairing of sequences from males
and females of nonmammalian species showed there to be no significant
difference between male and female sequences from a single species,
consistent with autosomal locations. The molecular distances between murine
Zfy-1, Zfy-2, and other ZFY-like sequences suggested that Zfy genes have
undergone a period of rapid evolutionary change not seen in human ZFY.
相似文献
110.
The phylogenetic position of Rhopalura ophiocomae (Orthonectida) based on 18S ribosomal DNA sequence analysis 总被引:2,自引:0,他引:2
Hanelt B; Van Schyndel D; Adema CM; Lewis LA; Loker ES 《Molecular biology and evolution》1996,13(9):1187-1191
The Orthonectida is a small, poorly known phylum of parasites of marine
invertebrates. Their phylogenetic placement is obscure; they have been
considered to be multicellular protozoans, primitive animals at a
"mesozoan" grade of organization, or secondarily simplified flatworm- like
organisms. The best known species in the phylum, Rhopalura ophiocomae, was
collected on San Juan Island, Wash. and a complete 18S rDNA sequence was
obtained. Using the models of minimum evolution and parsimony, phylogenetic
analyses were undertaken and the results lend support to the following
hypotheses about orthonectids: (1) orthonectids are more closely aligned
with triploblastic metazoan taxa than with the protist or diploblastic
metazoan taxa considered in this analysis; (2) orthonectids are not derived
members of the phylum Platyhelminthes; and (3) orthonectids and rhombozoans
are not each other's closest relatives, thus casting further doubt on the
validity of the phylum Mesozoa previously used to encompass both groups.
相似文献