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   238篇
  免费   16篇
林业   7篇
农学   4篇
  35篇
综合类   17篇
农作物   9篇
水产渔业   28篇
畜牧兽医   140篇
植物保护   14篇
  2023年   1篇
  2022年   6篇
  2021年   16篇
  2020年   9篇
  2019年   12篇
  2018年   9篇
  2017年   8篇
  2016年   10篇
  2015年   7篇
  2014年   4篇
  2013年   18篇
  2012年   7篇
  2011年   22篇
  2010年   8篇
  2009年   12篇
  2008年   16篇
  2007年   18篇
  2006年   7篇
  2005年   16篇
  2004年   16篇
  2003年   5篇
  2002年   5篇
  2001年   2篇
  2000年   3篇
  1999年   3篇
  1990年   1篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1973年   2篇
  1966年   1篇
排序方式: 共有254条查询结果,搜索用时 15 毫秒
81.
Veterinary Research Communications - Ceramide (CER), an important component of the extracellular lamellar lipids in the stratum corneum (SC), plays a critical role in maintaining the cutaneous...  相似文献   
82.
In this study, a retrospective analysis was conducted to assess the current aspects and predisposing factors of canine sterile panniculitis. Miniature dachshund, neutered, and younger dogs appeared to be predisposed. In addition, histories of previous surgery and injection were associated in 46.5% of the cases, with several types of surgical suture materials used. About 88% of the dogs had multifocal lesions, frequently with signs of systemic illnesses. Whereas systemic immunosuppressive therapy was effective in most dogs, surgical excision of lesions was rarely curative. In order to prevent recurrences, over 65% of the cases required prolonged immunosuppressive therapy. Polymorphism of canine alpha(1)AT gene was investigated as a candidate gene for sterile panniculitis. Eight polymorphisms were discovered in seven Miniature dachshunds by direct nucleotide sequencing, which included a 12-bp deletion, three non-synonymous single nucleotide polymorphisms, and four silent substitutions. Genotyping of the two polymorphisms, c.109_120del12 and c.483A>C, which identified at high incidence in the dachshunds, was conducted in 83 dogs of 6 popular breeds. The frequencies of neither polymorphism differed between Miniature dachshunds and other breeds, suggesting that neither is responsible for developing panniculitis.  相似文献   
83.
84.
Rainbow trout (Oncorhynchus mykiss) head kidney phagocytes precultured with a synthetic cytidine-phosphate-guanosine (CpG) oligodeoxynucleotide (ODN) displayed significantly higher phagocytic activity against Vibrio ordalii than phagocytes precultured with non-CpG ODN. However, head kidney phagocytes precultured with CpG ODN did not show enhanced phagocytic activity against polystyrene particles.  相似文献   
85.
Benzpyrimoxan (5-(1,3-dioxan-2-yl)-4-{[4-(trifluoromethyl)phenyl]methoxy}pyrimidine, NNI-1501) was discovered as a novel insecticide structurally characterized by a pyrimidine derivative substituted with 1,3-dioxanyl and 4-trifluoromethylbenzyloxy groups. The compound showed remarkable activity against nymphs of rice planthoppers, including strains resistant to existing insecticides. Furthermore, benzpyrimoxan had low adverse effects on pollinators and beneficial arthropods. Because of these features, benzpyrimoxan is expected to be a suitable part of an integrated pest management strategy. In this report, the history of the discovery to reach benzpyrimoxan and details of the structure–activity relationships are described.  相似文献   
86.
There are many paddy fields and large amounts of groundwater in the Tedori River Alluvial Fan in Ishikawa Prefecture, Japan. Water infiltration from paddy fields during irrigation may significantly contribute to groundwater recharge. Groundwater recharge is known to be one outcome of paddy farming, and in general is usually related to land use. However, a decreased area of paddy fields because of socioeconomic factors such as urbanization and increasing area of fallow fields has possibly affected the groundwater environment. Evaluation of the quantitative effect of paddy fields on groundwater is necessary for groundwater conservation. This study examined the relationship between differences in the depth of groundwater from just before the irrigation period to just after the first irrigation of paddy fields (increments of groundwater levels) in observation wells and the area of paddy fields around each well. The paddy areas within circular buffer zones, which were delineated at 0.2 km intervals between 0.2 and 2.0 km centered on each observation well, were calculated. A positive relationship was found between the rise in groundwater and the area of paddy field within different buffer zones at most wells. In addition, in the middle or upper part of the fan, the effect of changes in the area of paddy fields surrounding the well on the groundwater level rise was greater than that on the lower part of the fan.  相似文献   
87.
A six‐year‐old, neutered, female golden retriever was presented with generalised, dark purple to black cutaneous nodules and gastrointestinal haemorrhage. Histopathologically, all cutaneous nodules were diagnosed as benign cavernous haemangiomas. Endoscopic analysis revealed similar nodules in the oesophagus, stomach and duodenum. At laparotomy, similar nodules were seen on the visceral peritoneal lining of abdominal organs. Metastatic haemangiosarcoma was ruled out based on histological features and lack of primary tumour in spleen, liver or heart ultrasonographically. Blood loss associated with gastrointestinal haemorrhage was managed with blood transfusion. To the authors’ knowledge, this is the first canine case of multi‐system progressive angiomatosis resembling blue rubber bleb nevus syndrome in humans.  相似文献   
88.
We conducted a field survey in Japanese streams and rivers to generate useful information about whether the Japanese water quality standard for zinc (Zn) in the freshwater environment (30 μg/L) is over- or underprotective of the populations and communities of lotic benthic macroinvertebrates. Many macroinvertebrate populations were reduced and community characteristics were altered at two polluted sites with Zn concentrations above 1,000 μg/L as compared with control sites with Zn concentrations below 30 μg/L. In contrast, at least one site among three polluted sites with Zn concentrations of 80–126 μg/L experienced noncritical effects (i.e., no significant difference was observed between the sample mean at a polluted site and that at the control sites, and the sample mean was within the minimum–maximum range of those at the control sites) for most of the ten community metrics for diversity and abundance. In addition, the abundances of 95% of the dominant taxa were not always significantly lower at more than one polluted site (Zn concentrations, ≥80 μg/L). Our results suggest that Zn concentrations below approximately 100 μg/L are likely to protect most aspects of richness and abundance of the riverine macroinvertebrate communities in the study areas. This study shows a case that the Japanese Zn standard is likely overprotective of the macroinvertebrate populations and communities.  相似文献   
89.
In a Robinia-pseudoacacia-dominated coastal forest in Tottori prefecture Japan, the growth and survival of Pinus thunbergii seedlings and the natural regeneration of P. thunbergii was disturbed by R. pseudoacacia. In order to improve the growth of P. thunbergii seedling in the Tottori sand dune, we tried to find a mycorrhiza helper bacteria (MHB) from P. thunbergii mycorrhizosphere in a Tottori sand dune. Two MHB, Ralstonia sp. and Bacillus subtilis, were selected from the nine bacterial species isolated from the mycorrhizosphere of P. thunbergii. The bacterial effect on the ectomycorrhizal fungus Suillus granulatus was investigated by confrontation assay and a microcosm experiment. The confrontation assay showed that Ralstonia sp. promoted the hyphal growth of S. granulatus. Moreover, the S. granulatusP. thunbergii symbiosis was significantly stimulated by Ralstonia sp. and B. subtilis. Ralstonia sp. and B. subtilis were regarded as MHB associated with P. thunbergii. This is the first report of Ralstonia sp. as an MHB.  相似文献   
90.
The bacterium Wautersia [Ralstonia] basilensis has been shown to enhance the mycorrhizal symbiosis between Suillus granulatus and Pinus thunbergii (Japanese black pine). However, no information is available about this bacterium under field conditions. The objectives of this study were to detect W. basilensis in bulk and mycorhizosphere soils in a Japanese pine plantation in the Tottori Sand Dunes, determine the density of W. basilensis in soil, and determine the optimal cell density of W. basilensis for mycorrhizal formation in pine seedlings. We designed and validated 16S rRNA gene-targeted specific primers for detection and quantification of W. basilensis. SYBR Green I real-time PCR assay was used. A standard curve relating cultured W. basilensis cell density (103-108 cells ml−1) to amplification of DNA showed a strong linear relationship (R = 0.9968). The specificity of the reaction was confirmed by analyzing DNA melting curves and sequencing of the amplicon. The average cell density of W. basilensis was >4.8 × 107 cells g−1 of soil in the mycorrhizosphere and 7.0 × 106 cells g−1 in the bulk soil. We evaluated the W. basilensis cell density required for mycorrhizal formation using an in vitro microcosm with various inoculum densities ranging from 102 to 107 cells g−1 soil (104-109 cells ml−1). Cell densities of W. basilensis of >106 cells g−1 of soil were required to stimulate mycorrhizal formation. In vivo and in vitro experiments showed that W. basilensis was sufficiently abundant to enhance mycorrhizal formation in the mycorrhizosphere of Japanese black pine sampled from the Tottori Sand Dunes.  相似文献   
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