首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   290篇
  免费   20篇
  国内免费   1篇
林业   12篇
农学   3篇
  23篇
综合类   11篇
农作物   16篇
水产渔业   57篇
畜牧兽医   135篇
园艺   1篇
植物保护   53篇
  2022年   3篇
  2021年   15篇
  2020年   7篇
  2019年   8篇
  2018年   11篇
  2017年   10篇
  2016年   10篇
  2015年   5篇
  2014年   14篇
  2013年   12篇
  2012年   14篇
  2011年   18篇
  2010年   16篇
  2009年   13篇
  2008年   24篇
  2007年   22篇
  2006年   17篇
  2005年   20篇
  2004年   9篇
  2003年   26篇
  2002年   9篇
  2001年   10篇
  2000年   5篇
  1999年   2篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
  1994年   2篇
  1993年   3篇
  1990年   1篇
  1989年   1篇
排序方式: 共有311条查询结果,搜索用时 328 毫秒
121.
122.
We performed genome‐wide association studies (GWAS) using the BovineSNP50 array to detect significant single nucleotide polymorphisms (SNPs) that may affect the concentration of 22 free amino acids and three peptides in Japanese Black beef cattle. A total of 574 Japanese Black cattle and 40,657 SNPs from the array were used for this study. Genome‐wide significant SNPs were detected for β‐alanine (three SNPs on chromosomes 22 and 29) and taurine (26 SNPs on chromosome 22). Importantly, the top two SNPs for taurine were highly significant (= 6.2 × 10?21), and the frequency of the increase‐concentration allele (Q) for taurine was found to be 0.73. The Q allele frequency of this population was similar to that of the other unrelated Japanese Black cattle, but different from that of the other breeds. In addition, the significant SNPs were not associated with carcass traits or fatty acid compositions. Interestingly, the top three of the four most significant SNPs for taurine were located near solute carrier family 6, member 6 (SLC6A6), which is a membrane transporter for taurine. We also found two associated variants in the 5′‐upstream region of SLC6A6; however, they were less significantly associated than the SNPs from the BovineSNP50 array.  相似文献   
123.
The polymorphisms associated with economic traits in livestock animals provide useful information as genetic indicators for breeding improvement. Over the last two decades, several DNA markers have been developed in Japanese Black cattle; however, the effect of these markers differs across populations due to differences in their genetic structures and backgrounds. As such, there is a need to verify the effectiveness of these markers in each population. This review summarizes the effectiveness of previously reported markers on carcass traits and the development of novel DNA markers in a Japanese Black cattle population in Hyogo Prefecture. As result of genome wide association studies and resequencing analyses, two novel significant markers associated with meat quality-related traits (beef marbling and fatty acid composition) were developed. These findings will lead to the identification of responsible genes and polymorphisms and contribute to the development of novel DNA markers for numerous traits in various cattle populations.  相似文献   
124.
125.
Since 2002, papaya black rot has been spreading over several islands of Okinawa Prefecture, Japan. To devise a prevention strategy for the disease, microbiological research on the pathogen was conducted. Twelve strains were isolated from papaya infected with black rot showing symptoms such as water-soaked lesions on stems and petioles, black spots on fruits, and rotted leaves turning yellow with necrotic spots. Through Koch's postulates, we confirmed that the isolated strains caused papaya black rot. Bacteriological assays showed that the strains have characteristics different from the type strains of Erwinia mallotivora, E. papayae, and E. psidii. Moreover, 16S rDNA sequence similarity searches showed that the isolated strains had less than 98.6% similarity with type strains. Additionally, phylogenetic analysis of 16S rDNA sequences suggested that the isolated strains were possibly a novel species belonging to the genus Erwinia, as the strains formed an independent cluster and had low sequence similarity with the type strains. Earlier studies indicated that papaya black rot is caused by E. cypripedii. Therefore, we propose to add the Erwinia sp. isolated in this study to the list of papaya black rot pathogens.  相似文献   
126.
Journal of General Plant Pathology - A BIO-PCR was developed for the detection of potato blackleg pathogens, including Pectobacterium wasabiae (Pw), P. atrosepticum (Pa), P. carotovorum subsp....  相似文献   
127.
We synthesized 33 new phenylpiperazine derivatives and assessed their acaricidal activity. These derivatives were synthesized through sequential reactions consisting of the sulfonylation of 2-substituted 4-methylaniline with chlorosulfonic acid, reduction with red phosphorus and iodine, alkylation by alkyl halide, cyclization with bis(2-chloroethyl)amine hydrochloride, and N-substitution reaction of phenylpiperazines with various reagents. All phenylpiperazines synthesized were evaluated for acaricidal activity and their structure–activity relationships discussed, it was found that 4-substituted 1-[2-fluoro-4-methyl-5-(2,2,2-trifluoroethylsulfanyl)phenyl]piperazine derivatives exhibited good acaricidal activity. Among them, 1-[2-fluoro-4-methyl-5-(2,2,2-trifluoroethylsulfanyl)phenyl]-4-(trifluoromethylsulfonyl) piperazine showed the highest level of activity against Tetranychus urticae and provided a high level of activity against Tetranychus kanzawai and Panonychus citri. In addition, studies on the effect at various stages of T. urticae exhibited that this compound showed good activity against both adults and eggs.  相似文献   
128.
In rural areas of northern Laos, a commercially valuable pioneer tree species, paper mulberry (Broussonetia papyrifera L. Vent.) has been recommended for intercropping under plantations of commercial trees. However, less is understood about the growth of this pioneer tree species in the understorey and the mechanism underlying the shade intolerance. We measured growth characteristics for seedlings of paper mulberry under four light intensities. We compared the relative growth rates in aboveground biomass and standing leaf area (RGRmass and RGRleaf), light-capture efficiency, and seeding-level mass-based daily photosynthetic rates (A mass) with those of field-grown seedlings of eight shade-tolerant species to identify factors potentially responsible for shade-intolerance. Most growth traits of the paper mulberry seedlings did not differ consistently from those of the shade tolerant species. The ecophysiological–architectural model software showed higher A mass and RGRmass capacity in paper mulberry than in shade-tolerant species. Despite their higher RGRmass, paper mulberry seedlings had negative RGRleaf under shaded conditions due to short leaf lifespan. The linear RGRmass–RGRleaf relationship for paper mulberry had a high RGRmass intercept, indicating that a high RGRmass was required to provide positive RGRleaf. Progressive decreases in standing leaf area with time, and possibly photosynthesis, appear to be responsible for the shade-intolerance of paper mulberry. Although intercropping of paper mulberry has been suggested in the species’ native region, understorey cultivation of paper mulberry would only be possible with relatively open canopies.  相似文献   
129.
130.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号