全文获取类型
收费全文 | 83篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
87篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 3篇 |
2012年 | 5篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 7篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有87条查询结果,搜索用时 15 毫秒
1.
Young-Jun Park Tomotaro Nishikawa Norihiko Tomooka Kazuhiro Nemoto 《Molecular breeding : new strategies in plant improvement》2012,30(1):511-520
Polymorphisms at the Waxy locus of Amaranthus caudatus L. collected from a wide range of regions were used to investigate genetic diversity and mutation sites. A comparison of the Waxy locus revealed a very high level of sequence conservation. This result clearly showed low environmental and evolutionary variability in the Waxy gene. We also performed screening to confirm the mutation sites in the coding sequences of all accessions. The results indicate that one insertion in the coding region of Waxy genes was responsible for the change in perisperm starch leading to the waxy phenotype in all accessions of this species, and thus that a single mutation event altered the regulation of the Waxy gene during the domestication of this crop. In addition, phylogenetic analysis showed that waxy phenotypes within each of three species, A. caudatus, A. cruentus and A. hypochondriacus, originated separately or differentiated from nonwaxy phenotypes of each species through a single mutational event (i.e., a frame shift or base substitution). We also compared obvious structural features of the coding sequence of waxy and nonwaxy phenotypes with those of low-amylose phenotypes in A. caudatus. The Waxy coding sequences of low-amylose phenotypes do not show polymorphisms and are identical with those of waxy phenotypes. This could mean that there is another gene that encodes a key enzyme responsible for amylose synthesis as the elementary quantity in tissues other than perisperm in A. caudatus. 相似文献
2.
Although microorganisms largely drive many ecosystem processes, the relationship between microbial composition and their functioning remains unclear. To tease apart the effects of composition and the environment directly, microbial composition must be manipulated and maintained, ideally in a natural ecosystem. In this study, we aimed to test whether variability in microbial composition affects functional processes in a field setting, by reciprocally transplanting riverbed sediments between low- and high-salinity locations along the Nonesuch River (Maine, USA). We placed the sediments into microbial ‘cages'' to prevent the migration of microorganisms, while allowing the sediments to experience the abiotic conditions of the surroundings. We performed two experiments, short- (1 week) and long-term (7 weeks) reciprocal transplants, after which we assayed a variety of functional processes in the cages. In both experiments, we examined the composition of bacteria generally (targeting the 16S rDNA gene) and sulfate-reducing bacteria (SRB) specifically (targeting the dsrAB gene) using terminal restriction fragment length polymorphism (T-RFLP). In the short-term experiment, sediment processes (CO2 production, CH4 flux, nitrification and enzyme activities) depended on both the sediment''s origin (reflecting differences in microbial composition between salt and freshwater sediments) and the surrounding environment. In the long-term experiment, general bacterial composition (but not SRB composition) shifted in response to their new environment, and this composition was significantly correlated with sediment functioning. Further, sediment origin had a diminished effect, relative to the short-term experiment, on sediment processes. Overall, this study provides direct evidence that microbial composition directly affects functional processes in these sediments. 相似文献
3.
Resistance of wild and cultivated rice bean (Vigna umbellata [Thunberg] Ohwi and Ohashi) to three bruchid species, Callosobruchus chinensis L., Callosobruchus maculatus F., and Callosobruchus analis F., was evaluated. All but three accessions of cultivated, and all wild rice bean accessions tested, exhibited complete resistance to all three bruchid species. Rice bean seeds with seed coat removed also showed complete resistance to the three bruchid species. Results indicate that physical attributes and/or chemical(s) present in the seed coat of rice bean are not the main factors responsible for resistance. Feeding tests were performed by using artificial beans prepared with varying proportions of rice bean (resistant) and azuki bean (susceptible) flour. Number of bruchid adults that emerged decreased, and larval developmental period (days) was extended, when artificial beans with an increasing proportion of rice bean flour were used. These tests revealed that a chemical compound(s) contained in the cotyledon of rice bean has an inhibitory effect on the growth of these bruchid species. The results also indicate that the chemical(s) in rice bean cotyledon is most effective against C. maculatus. 相似文献
4.
Ho PP Fontoura P Platten M Sobel RA DeVoss JJ Lee LY Kidd BA Tomooka BH Capers J Agrawal A Gupta R Zernik J Yee MK Lee BJ Garren H Robinson WH Steinman L 《Journal of immunology (Baltimore, Md. : 1950)》2005,175(9):6226-6234
Targeting pathogenic T cells with Ag-specific tolerizing DNA vaccines encoding autoantigens is a powerful and feasible therapeutic strategy for Th1-mediated autoimmune diseases. However, plasmid DNA contains abundant unmethylated CpG motifs, which induce a strong Th1 immune response. We describe here a novel approach to counteract this undesired side effect of plasmid DNA used for vaccination in Th1-mediated autoimmune diseases. In chronic relapsing experimental autoimmune encephalomyelitis (EAE), combining a myelin cocktail plus IL-4-tolerizing DNA vaccine with a suppressive GpG oligodeoxynucleotide (GpG-ODN) induced a shift of the autoreactive T cell response toward a protective Th2 cytokine pattern. Myelin microarrays demonstrate that tolerizing DNA vaccination plus GpG-ODN further decreased anti-myelin autoantibody epitope spreading and shifted the autoreactive B cell response to a protective IgG1 isotype. Moreover, the addition of GpG-ODN to tolerizing DNA vaccination therapy effectively reduced overall mean disease severity in both the chronic relapsing EAE and chronic progressive EAE mouse models. In conclusion, suppressive GpG-ODN effectively counteracted the undesired CpG-induced inflammatory effect of a tolerizing DNA vaccine in a Th1-mediated autoimmune disease by skewing both the autoaggressive T cell and B cell responses toward a protective Th2 phenotype. These results demonstrate that suppressive GpG-ODN is a simple and highly effective novel therapeutic adjuvant that will boost the efficacy of Ag-specific tolerizing DNA vaccines used for treating Th1-mediated autoimmune diseases. 相似文献
5.
The impact of masticatory ability as evaluated by salivary flow rates on obesity in japanese: The Toon health study 下载免费PDF全文
6.
Komine A Suenaga M Nakao K Tsuji T Tomooka Y 《Biochemical and biophysical research communications》2007,355(3):758-763
In order to investigate tooth development, several cell lines of the dental epithelium and ectomesenchyme have been established. However, no attempt has been reported to regenerate teeth with cell lines. Here, we have established several clonal cell lines of the dental epithelium from a p53-deficient fetal mouse. They expressed specific markers of the dental epithelium such as ameloblastin and amelogenin. A new method has been developed to bioengineer tooth germs with dental epithelial and mesenchymal cells. Reconstructed tooth germs with cell lines and fetal mesenchymal cells were implanted under kidney capsule. The germs regenerated teeth with well-calcified structures as seen in natural tooth. Germs without the cell lines developed bone. This is the first success to regenerate teeth with dental epithelial cell lines. They are useful models in vitro for investigation of mechanisms in morphogenesis and of cell lineage in differentiation, and for clinical application for tooth regeneration. 相似文献
7.
We attempted to isolate genes involved in neuronal differentiation from a cell line 2Y-3t newly established from a mouse cerebellum. 2Y-3t cells proliferate in serum-containing medium and differentiate into neurons in serum-free medium. We took a subtraction method to isolate genes differentially expressed in differentiated cells and 17 cDNA clones were isolated. Functions of 6 cDNA clones are unknown. No. 60 cDNA clone has 723 nucleotides encoding 240 amino acid residues. It contains two putative EF-hand motifs and a coiled-coil region at C terminal end. Expression of the clone was undetectable at embryonic stage and was increased in brain during development. In situ hybridization showed that the expression was observed predominantly in neurons, suggesting that the protein may play roles in the neuronal differentiation and function. 相似文献
8.
To better understand the genetic diversity of the wild relatives of rice (Oryza sativa L.) in the O. officinalis species complex repetitive DNA markers were obtained from the diploid species of this complex. One cloned sequence from O. eichingeri gave intense hybridization signals with all species of the O. officinalis complex. This 242 bp clone, named pOe.49, has a copy number from 0.9 to 4.0 × 104 in diploid species of this complex. Analysis of the primary structure and database searches revealed homology of pOe.49 to
a number of sequences representing part of the integrase coding domain of retroviruses and gypsy-like retrotransposons. Sequencing of specific PCR products confirmed that pOe.49 is part of a gypsy-like retrotransposon. RFLP analysis was used to study the genomic organisation of pOe.49 among 30 accessions of the O. officinalis complex using 10 restriction enzymes. Diversity analysis based on 120 polymorphic fragments obtained from the RFLP assay
grouped the O. officinalis complex accessions by genome, species and eco-geographic groups. The results suggest that, with further characterization,
this retrotransposon-like DNA sequence may be useful for phylogenetic analysis of species in the O. officinalis complex.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Masahiro Hiratochi Akiyori Fujiwara Hiroshi Kitani Taisen Iguchi Teruyo Sakakura Yasuhiro Tomooka 《Development, growth & differentiation》1998,40(1):59-65
Mouse neural precursor cells (NPC) were dissociated from fetal heads at the 10th day of gestation. When clumps of NPC were cultured in collagen gel, they grew and reorganized neural tube-like structures in medium containing fetal calf serum at 10% and supplemented with insulin, transferrin, cholera toxin and selenite. However, dissociated NPC died when they were cultured in collagen gel at low density in the same medium. Addition of fibroblast growth factor-2 (FGF-2) to this culture stimulated growth of NPC and formation of neural tube-like structures. The requirement for FGF-2 disappeared in high seeding density culture: they grew and formed neural tube-like structures without FGF-2. The structures formed in collagen gel were immunohistochemically positive against anti-FGF-2 antibody. The results show that the three-dimensional culture system provides a useful tool to study the roles of FGF-2 in morphogenesis of the central nervous system. 相似文献
10.