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排序方式: 共有190条查询结果,搜索用时 31 毫秒
111.
Genome sequence of Silicibacter pomeroyi reveals adaptations to the marine environment 总被引:2,自引:0,他引:2
Moran MA Buchan A González JM Heidelberg JF Whitman WB Kiene RP Henriksen JR King GM Belas R Fuqua C Brinkac L Lewis M Johri S Weaver B Pai G Eisen JA Rahe E Sheldon WM Ye W Miller TR Carlton J Rasko DA Paulsen IT Ren Q Daugherty SC Deboy RT Dodson RJ Durkin AS Madupu R Nelson WC Sullivan SA Rosovitz MJ Haft DH Selengut J Ward N 《Nature》2004,432(7019):910-913
Since the recognition of prokaryotes as essential components of the oceanic food web, bacterioplankton have been acknowledged as catalysts of most major biogeochemical processes in the sea. Studying heterotrophic bacterioplankton has been challenging, however, as most major clades have never been cultured or have only been grown to low densities in sea water. Here we describe the genome sequence of Silicibacter pomeroyi, a member of the marine Roseobacter clade (Fig. 1), the relatives of which comprise approximately 10-20% of coastal and oceanic mixed-layer bacterioplankton. This first genome sequence from any major heterotrophic clade consists of a chromosome (4,109,442 base pairs) and megaplasmid (491,611 base pairs). Genome analysis indicates that this organism relies upon a lithoheterotrophic strategy that uses inorganic compounds (carbon monoxide and sulphide) to supplement heterotrophy. Silicibacter pomeroyi also has genes advantageous for associations with plankton and suspended particles, including genes for uptake of algal-derived compounds, use of metabolites from reducing microzones, rapid growth and cell-density-dependent regulation. This bacterium has a physiology distinct from that of marine oligotrophs, adding a new strategy to the recognized repertoire for coping with a nutrient-poor ocean. 相似文献
112.
介绍了引文索引的功能及其异化过程,探讨了国内外科研学术绩效评价中引文数据的应用,分析了SCI及其衍生产品的科研绩效评价功能,阐述了SCI来源刊及其分区依据。 相似文献
113.
114.
详细地介绍了一种利用电磁涡流信号检测淬火钢轨硬度的新型无损检测装置 .利用该装置可连续地实现钢轨踏面硬度的检测 ,并且通过应用计算机信号处理技术和图形技术 ,使得该装置的检测精度达到了工业测量的要求 . 相似文献
115.
Smith UM Consugar M Tee LJ McKee BM Maina EN Whelan S Morgan NV Goranson E Gissen P Lilliquist S Aligianis IA Ward CJ Pasha S Punyashthiti R Malik Sharif S Batman PA Bennett CP Woods CG McKeown C Bucourt M Miller CA Cox P Algazali L Trembath RC Torres VE Attie-Bitach T Kelly DA Maher ER Gattone VH Harris PC Johnson CA 《Nature genetics》2006,38(2):191-196
Meckel-Gruber syndrome is a severe autosomal, recessively inherited disorder characterized by bilateral renal cystic dysplasia, developmental defects of the central nervous system (most commonly occipital encephalocele), hepatic ductal dysplasia and cysts and polydactyly. MKS is genetically heterogeneous, with three loci mapped: MKS1, 17q21-24 (ref. 4); MKS2, 11q13 (ref. 5) and MKS3 (ref. 6). We have refined MKS3 mapping to a 12.67-Mb interval (8q21.13-q22.1) that is syntenic to the Wpk locus in rat, which is a model with polycystic kidney disease, agenesis of the corpus callosum and hydrocephalus. Positional cloning of the Wpk gene suggested a MKS3 candidate gene, TMEM67, for which we identified pathogenic mutations for five MKS3-linked consanguineous families. MKS3 is a previously uncharacterized, evolutionarily conserved gene that is expressed at moderate levels in fetal brain, liver and kidney but has widespread, low levels of expression. It encodes a 995-amino acid seven-transmembrane receptor protein of unknown function that we have called meckelin. 相似文献
116.
Feng JQ Ward LM Liu S Lu Y Xie Y Yuan B Yu X Rauch F Davis SI Zhang S Rios H Drezner MK Quarles LD Bonewald LF White KE 《Nature genetics》2006,38(11):1310-1315
The osteocyte, a terminally differentiated cell comprising 90%-95% of all bone cells, may have multiple functions, including acting as a mechanosensor in bone (re)modeling. Dentin matrix protein 1 (encoded by DMP1) is highly expressed in osteocytes and, when deleted in mice, results in a hypomineralized bone phenotype. We investigated the potential for this gene not only to direct skeletal mineralization but also to regulate phosphate (P(i)) homeostasis. Both Dmp1-null mice and individuals with a newly identified disorder, autosomal recessive hypophosphatemic rickets, manifest rickets and osteomalacia with isolated renal phosphate-wasting associated with elevated fibroblast growth factor 23 (FGF23) levels and normocalciuria. Mutational analyses showed that autosomal recessive hypophosphatemic rickets family carried a mutation affecting the DMP1 start codon, and a second family carried a 7-bp deletion disrupting the highly conserved DMP1 C terminus. Mechanistic studies using Dmp1-null mice demonstrated that absence of DMP1 results in defective osteocyte maturation and increased FGF23 expression, leading to pathological changes in bone mineralization. Our findings suggest a bone-renal axis that is central to guiding proper mineral metabolism. 相似文献
117.
Graham RR Kozyrev SV Baechler EC Reddy MV Plenge RM Bauer JW Ortmann WA Koeuth T González Escribano MF;Argentine Spanish Collaborative Groups Pons-Estel B Petri M Daly M Gregersen PK Martín J Altshuler D Behrens TW Alarcón-Riquelme ME 《Nature genetics》2006,38(5):550-555
Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by activation of the type I interferon (IFN) pathway. Here we convincingly replicate association of the IFN regulatory factor 5 (IRF5) rs2004640 T allele with SLE in four independent case-control cohorts (P = 4.4 x 10(-16)) and by family-based transmission disequilibrium test analysis (P = 0.0006). The rs2004640 T allele creates a 5' donor splice site in an alternate exon 1 of IRF5, allowing expression of several unique IRF5 isoforms. We also identify an independent cis-acting variant associated with elevated expression of IRF5 and linked to the exon 1B splice site. Haplotypes carrying the variant associated with elevated expression and lacking the exon 1B donor site do not confer risk of SLE. Thus, a common IRF5 haplotype driving elevated expression of multiple unique isoforms of IRF5 is an important genetic risk factor for SLE, establishing a causal role for type I IFN pathway genes in human autoimmunity. 相似文献
118.
Genetic variation in Mon1a affects protein trafficking and modifies macrophage iron loading in mice 总被引:2,自引:0,他引:2
Wang F Paradkar PN Custodio AO McVey Ward D Fleming MD Campagna D Roberts KA Boyartchuk V Dietrich WF Kaplan J Andrews NC 《Nature genetics》2007,39(8):1025-1032
We undertook a quantitative trait locus (QTL) analysis in mice to identify modifier genes that might influence the severity of human iron disorders. We identified a strong QTL on mouse chromosome 9 that differentially affected macrophage iron burden in C57BL/10J and SWR/J mice. A C57BL/10J missense allele of an evolutionarily conserved gene, Mon1a, cosegregated with the QTL in congenic mouse lines. We present evidence that Mon1a is involved in trafficking of ferroportin, the major mammalian iron exporter, to the surface of iron-recycling macrophages. Differences in amounts of surface ferroportin correlate with differences in cellular iron content. Mon1a is also important for trafficking of cell-surface and secreted molecules unrelated to iron metabolism, suggesting that it has a fundamental role in the mammalian secretory apparatus. 相似文献
119.
以火箭式激振器为震源对高大结构物(即云南景洪澜沧江大桥主塔)进行了现场动力测试和分析,利用实测结构体系的动力特性,取得了场地土边界元参数,在考虑了土与结构相互作用的基础上,为选取全桥的抗震设计参数提供合理依据. 相似文献
120.
通过构建以MDR1启动子为启动序列的荧光素酶报告基因载体,建立基于双荧光素酶报告基因系统的多药耐药抑制剂筛选模型。从HCT-8细胞中提取DNA并克隆含有MDR1基因启动子的序列。将该序列重组到荧光素酶报告基因载体pGL-3-Basic的启动区域中,从而构建报告基因载体pGL-MDR1。将pGL-MDR1和pRL-TK载体共转染到HCT-8和HCT-8/VCR细胞中,建立用于筛选多药耐药抑制剂的方法。通过调节不同载体的比例来优化转染效率。通过MDR1基因激活剂(热诱导)和抑制剂(EGCG)来验证该方法。通过直接测序法验证了pGL-MDR1含有MDR1基因启动子序列且没有出现碱基突变。在n(pGL-MDR1)∶n(pRL-TK)=5∶5时,转染效率最高并具有最高的荧光素酶活性。通过MDR1基因激活处理后表现为时间依赖性地激活MDR1基因的表达,而MDR1基因抑制剂的作用则相反。 相似文献