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1.
Resistance tests were made on seedlings of transformed lines of Nicotiana benthamiana which contain a transgene encoding the coat protein (CP) gene of a Scottish isolate of potato mop-top virus (PMTV). This transgene has been reported to confer strong resistance to the PMTV isolate from which the transgene sequence was derived and also to a second Scottish isolate. Plants of lines of the transgenic N. benthamiana were as resistant to two Swedish and two Danish PMTV isolates as to a Scottish isolate, and of five lines tested, greater than 93.5% of transgenic plants were immune. The coat protein gene sequences of these four Scandinavian isolates were very similar to those of the two Scottish isolates. The greatest divergence between the isolates was three amino acid changes and there was less than 2% change in CP gene nucleotide sequence. It is concluded that the PMTV CP transgene used in these experiments could confer resistance against isolates from different geographical areas because it is becoming apparent that the CP genes of PMTV isolates are highly conserved.  相似文献   
2.
Two virus isolates from water samples — one from a small stream in South Western Germany and another one from the Havel river in North Eastern Germany c. 500 km away, proved to be strains, named S and H, respectively, of a new Tombusvirus for which the name Havel river virus (HaRV) had been suggested previously in a brief account. Immunoelectron microscopical decoration tests and sequence comparisons of the coat proteins indicated that the two HaRV strains are only distantly related to known Tombusviruses. The closest relationships were found to Cucumber necrosis virus. Nothing is known about their natural hosts. Because the S strain of HaRV was isolated in a woody area from a small stream close to its origin, they may be pathogens of trees or wild plants in such habitats.  相似文献   
3.
The high-speed access for medical digital image sequences was restricted to special device and complicated system in the past. The authors present a new method of high-speed access for medical digital image sequences which can be performed on general computer by means of the combination of Serial ATA(SATA) and Redundant Array of Independent Disk(RAID).Then they introduce the scheme of system configuration and software program. Lastly the testing result is given and the speediness,cheapness and conveniency of this method are elucidated.  相似文献   
4.
根据曼陀罗属核糖体基因转录间隔区(ITS)序列设计通用引物,得到33个不同来源的曼陀罗属植物的ITS序列,并以小天仙子(Hyoscyamus bohemicus)为外群,应用遗传距离与系统树分析法对曼陀罗属植物之间的分类进行了初步探讨。结果表明:在供试样品中,紫花曼陀罗(Datura tatula)和曼陀罗(Daturastramonium)的ITS序列完全相同;多刺曼陀罗(Datura ferox)、栎叶曼陀罗(Datura quercifolia)和曼陀罗(Datura stramonium)之间的亲缘关系很近;紫花曼陀曼(Datura tatula)、曼陀罗(Datura stramonium)、无刺曼陀罗(Datura inermis)和光滑曼陀罗(Datura laevis)4个种间不存在遗传距离;传统分类中曼陀罗属的Dutra亚属内除光曼陀罗(Datura leichhardtii)和异色曼陀罗(Datura discolor)在ITS序列表现为比较独立的2个种外,其他各种间的亲缘关系也较近;在ITS序列上湿地曼陀罗(Datura ceratocaula)与曼陀罗(Daturastramonium...  相似文献   
5.
基于数字水印技术和多媒体内容认证技术,提出买卖双方交互协议。该协议可以明确确认交易双方的身份,有效地防止了购买者水印被盗用的可能性,并很容易判定所购得的数字产品是否被篡改。  相似文献   
6.
The molecular epidemiology of the infectious disease caused by feline calcivirus (FCV) in Japan was investigated by analysing the phylogenetic relationship among 21 Japanese field isolates, including the F4 strain, and 30 global isolates. Parts of the capsid gene (B–F) of the isolates were amplified by RT-PCR, and the amino acid sequences were compared with those from the global isolates. Thirty-seven and 14 out of a total of 51 isolates were clustered into two distinct genogroups, I and II respectively, by UPGMA and NJ analysis. Seven of the 21 Japanese isolates (33%) fell into group I together with 30 global isolates, while the other 14 Japanese isolates (67%) belonged to group II. The bootstrap repetition analysis of groups I and II formed by the NJ method gave a value of 99.0%. The 14 latter Japanese isolates were clearly separated from the isolates in group I, and they were different from any previously known FCV, forming a new genogroup, which implies that this lineage has been confined to Japan. Comparing the amino acid sequences shared by groups I and II, the amino acid at position 377 in B region was asparagine (Asn or Asp (NH2)) in group I, while it was lysine (Lys) in all the strains in group II. Similarly, the amino acid at position 539 in the F region was alanine (Ala) or proline (Pro) in group I, while it was valine (Val) in group II; glycine (Gly) at position 557 in group I was serine (Ser) in Group II; and phenylalanine (Phe) or leucine (Leu) at position 566 in genogroup I was tyrosine (Tyr) in group II.  相似文献   
7.
根据猪繁殖与呼吸综合征病毒(PRRSV)的核衣壳蛋白编码基因序列设计了一对特异性引物P1/P2。扩增出大小为294bp的目的片段;再针对这个基因片段。设计合成4条寡核苷酸探针。其中反向引物的5’端用荧光素Cy3标记。以荧光标记不对称PCR技术为基础。通过将单链PCR产物与芯片杂交实现对PRRSV的检测。建立PRRSV的基因芯片检测方法。利用该方法对39份猪组织样品进行检测。与RT—PCR检测方法相比。本方法具有良好的特异性和敏感性。试验结果表明用该方法快速检测病料组织中PRRSV是可行的,对该病的进行快速诊断和分子流行病学调查具有重要意义。  相似文献   
8.
Fourteen Morchella samples (eleven from Yunnan and three from Zhejiang Provinces) were selected on the basis of differences in fruit body morphology. Ribosomal DNA internal transcribed spacers (ITS) were amplified in each case using the universal primer pair, ITS-1 and ITS-4, and the amplification products were purified and sequenced. Comparisons with sequence data in GenBank revealed that the 11 Morchella isolates collected from Yunnan belonged to four species: Morchella elata, Morchella conica, Morchella crassipes and Morchella costata. The three isolates collected from Zhejiang Province (M12, M13 and M14) were designated as unknown Morchella species. When Verpa conica (AJ544206) (from the genus Verpa belonging to the same family as Morchella) was taken as the outgroup, the 14 isolates formed three groups, M. elata, M. costata (Group 1); Morchella esculenta, M. conica (Group 2); and M. crassipes, M12, M13 and M14 (Group 3).  相似文献   
9.
设{εi,i≥1}为PA序列,Eεi=0,supE(ε^2j)〈∞,对某个r〉2及占〉δ,supE|εj|^r+δ〈∞,u(n)=O(n^(r-2)(r+δ)/2δ,在PA序列误差下,讨论了非参数回归函数加权核估计的相合性.  相似文献   
10.
【目的】试验旨在揭示终端父本皮特兰猪与杜洛克猪在人工选择作用下重要经济性状呈现出表型趋同的基因组变化特征。【方法】利用376头皮特兰猪、451头杜洛克猪品系Ⅰ、841头杜洛克猪品系Ⅱ和497头杜洛克猪品系Ⅲ群体的50K SNP芯片数据,以100 kb窗口、50 kb步长计算综合单倍型评分(iHS)和等位基因频率差(△AF),分别取前5%作为猪群体内、群体间的基因组选择信号候选区域;利用bedtools分别对iHS、△AF按照左右200 kb进行合并,每2个群体间合并后的iHS、△AF统计量的重叠区域定义为性状趋同区域,并挖掘该区域与猪重要经济性状相关的平行选择信号。【结果】iHS结果显示,在皮特兰猪和杜洛克猪4个群体内共检测到5 112个选择信号候选区域,总长约487.51 Mb。基于△AF方法,于皮特兰猪和杜洛克猪每2个群体间共检测到9 579个选择信号显著区域,总长约913.50 Mb。基于合并后的iHS和△AF,共检测到52个性状趋同区域,总长约4.67 Mb,注释到88个与猪的繁殖、胴体和肉质等性状相关的平行选择候选基因。【结论】皮特兰猪和杜洛克猪群体间存在性状趋同的基因组选择区域有52个,平行选择信号主要涉及猪的繁殖、胴体及肉质等重要经济性状,这与瘦肉型猪种相同的育种方向相关,这些关键基因的发现可为后续商业猪品种遗传改良提供参考。  相似文献   
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