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521.
522.
哲罗鱼(Hucho taimen)染色体组型与DNA含量分析 总被引:1,自引:0,他引:1
采用体内注射PHA和秋水仙素、肾细胞短期培养、常规空气干燥法制备哲罗鱼(Hucho taimen)的染色体。对其肾细胞染色体数目统计分析表明,哲罗鱼染色体组有84条染色体,核型公式为2n=18m+16sm+34st+16t,其染色体总臂数(NF)为118。采用流式细胞分析仪测定哲罗鱼的DNA含量,与鸡血细胞标准对照的比值为2.23±0.17,以鸡红细胞DNA含量2.30pg·N~(-1)计,则哲罗鱼的体细胞DNA含量为5.12pg·N~(-1)。哲罗鱼染色体数目和DNA含量体现为四倍体特征。 相似文献
523.
RAPD技术是由 Williams[1]和 Welsh[2 ]领导的两个科研小组于 1 990年几乎同时独立创立的一种 DNA多态性分析技术 ,它的原理是利用一系列随机排列的寡核苷酸单链引物 ,以研究对象的基因组 DNA为模板进行 PCR扩增 ,通过扩增产物 DNA片段的多态性来检测基因组 DNA的多态性。该技术已被广泛地应用于种质鉴定、遗传多样性、亲缘关系及系统分类研究 [3~ 6]。但对海水鱼类RAPD研究报道较少。红鳍笛鲷 (L utjanus erythopterus Bloch)、紫红笛鲷 (L utjanus argentimaculatus Forskal)和勒氏笛鲷 (L utjanus russelli Bleeker)具有… 相似文献
524.
运用高通量测序技术分析微型生物多样性时,生物学重复间常表现出明显的异质性,这可能是高比例的稀有可操作分类单元(operated taxonomic unit, OTU)造成的“假象”。为明晰陆架海区站位间及同一站位重复间底栖纤毛虫群落的异质性水平,并探明稀有OTU与群落异质性的关系,给出去除稀有OTU阈值的科学建议。本研究在东海选取具有明显环境梯度的4个站位,每站位采集3个重复沉积物,采用高通量测序技术研究纤毛虫群落与分布。研究表明同一站位重复间群落不相似度在30%~34%,重复间群落的高差异性会掩盖地理距离较近的站位间差异(33%)。各个站位重复间共有OTU分别占该站位检获的总OTU数的34.4%, 31.9%, 39.5%和36.5%,而序列数基本占据94%以上。相对丰度小于0.1%的OTU占总OTU数的80%。依次去除相对丰度低于0.01%至0.1%的OTU,发现去除稀有OTU能够有效降低重复间差异,去除越稀有的OTU,降低效果越强;对站位之间的差异影响较小,且站位差异越大影响越小。稀有OTU的分布随机性极强,基本与站位无关。相对丰度低于0.015%的OTU是造成重复间群落异质性... 相似文献
525.
Pituitary adenylate cyclase activating polypeptide(PACAP)and growth hormone-releasing hormone(GHRH)play important roles in the GH/IGF growth axis in fishes.To determine whether epigenetic change is involved in the regulation of pacap and ghrh responses to low salinity stress in Cynoglossus semilaevis,the correlation between growth traits,DNA methylation status and gene expression level in low salinity(15,S15)and optimal salinity(30,S30)at day 7(D7)and day 60(D60)were analyzed.Results showed that exposure to low salinity for 60 days attenuated C.semilaevis growth rate.Under low salinity,DNA methylation level of pacap promoter increased in females and decreased in males at day 7,but inverted at day 60.Additionally,pacap expression was up-regulated in both males and females.The pacap promoter methylation level was higher and expression level was lower in female than in male.The results suggest that pacap promoter methylation level is negatively correlated to mRNA level and positively correlated to body weight,while gene expression level is negatively related with body weight.With the decrease of salinity,DNA methylation level of ghrh promoter and exon1,as well as its gene expression displayed minor changes.Overall,pacap gene seems to play an important role in fish growth,contributing to female growth superiority,while ghrh gene seems not pertinent under salinity stress.The results indicate that low salinity potentially affects fish growth through regulating DNA methylation in pacap promoter.This study expands the understanding of the molecular mechanism of how salinity modulates fish growth from the epigenetic perspective. 相似文献
526.
SARKAR Provakar ISLAM Md Jayedul HABIB AHMShafiullah NEOGI Amit Kumer HABIB Kazi Ahsan 《中国海洋大学学报(英文版)》2021,20(2)
The present work documented two snapper species, Lutjanus fulvus Forster, 1801 and Lutjanus erythropterus Bloch, 1790, recently collected from the Saint Martin's Island, Bay of Bengal, Bangladesh, during a survey on coral associated fishes of Bangladesh from July 2017 to September 2018. These two species were identified with morphological characteristics and by analyzing partial mitochondrial COI sequences. The document also included an updated checklist of snappers available in Bangladesh. 相似文献
527.
Effects of DNA extraction and universal primers on 16S rRNA gene-based DGGE analysis of a bacterial community from fish farming water 总被引:3,自引:0,他引:3
Among many reports investigating microbial diversity from environmental samples with denaturing gradient gel electrophoresis (DGGE), limited attention has been given to the effects of universal primers and DNA extraction on the outcome of DGGE analysis. In this study, these effects were tested with 16S rRNA gene-based DGGE on a bacterial community from farming water samples. The results indicate that the number of discernable bands in the DGGE fingerprint differed with the primer pairs used; the bands produced by 63f/518r, 341f/926r and 933f/1387r primer pairs were obviously fewer than those by 968f/1401r. Also, we found that each DNA extraction method resulted in different community profiles, reflected by the number and intensity of bands in the DGGE fingerprint. Furthermore, the main bands (theoretically representing dominant bacteria) differed with the extraction methods applied. It is therefore believed that the effects of universal primers and DNA extraction should be given more attention and carefully chosen before performing an investigation into a new environment with DGGE. 相似文献
528.
三种笛鲷属鱼类的随机扩增多态性DNA初步研究 总被引:1,自引:0,他引:1
RAPD技术是由Williams和Welsh领导的两个科研小组于1990年几乎同时独立创立的一种DNA多态性分析技术,它的原理是利用一系列随机排列的寡核苷酸单链引物,以研究对象的基因组DNA为模板进行PCR扩增,通过扩增产物DNA片段的多态性来检测基因组DNA的多态性。 相似文献
529.
530.