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   75篇
  免费   3篇
林业   5篇
农学   6篇
  13篇
综合类   3篇
农作物   1篇
水产渔业   6篇
畜牧兽医   37篇
园艺   3篇
植物保护   4篇
  2022年   1篇
  2021年   1篇
  2020年   3篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   1篇
  2014年   5篇
  2013年   4篇
  2012年   5篇
  2011年   11篇
  2010年   7篇
  2009年   7篇
  2008年   7篇
  2007年   3篇
  2006年   2篇
  2005年   4篇
  2004年   3篇
  2003年   4篇
  2002年   2篇
  2001年   1篇
  1997年   1篇
  1996年   1篇
  1993年   1篇
  1979年   1篇
排序方式: 共有78条查询结果,搜索用时 15 毫秒
11.
In this study, synchronous spontaneous, independent liver and gallbladder tumours were detected in a Bearded dragon (Pogona vitticeps). The multiple tumours consisted of intrahepatic cholangiocarcinoma as well as in situ adenocarcinoma and two adenomas of the gallbladder. The biliary epithelial cells and the cholangiocarcinoma showed membranous cross-immunoreactivity for claudin-7. The gallbladder epithelial cells, its adenoma and adenocarcinoma showed basolateral cross-reactivity for claudin-7. We think that the humanised anti-claudin-7 antibody is a good marker for the detection of different primary cholangiocellular and gallbladder tumours in Bearded dragons. The cholangiocytes, the cholangiocarcinoma, the endothelial cells of the liver and the epithelial cells and gallbladder tumours all showed claudin-5 cross-reactivity. The humanised anti-cytokeratin AE1-AE3 antibody showed cross-reactivity in the biliary epithelial cells, cholangiocarcinoma cells, epithelial cells and tumour cells of the gallbladder. It seems that this humanised antibody is a useful epithelial marker for the different neoplastic lesions of epithelial cells in reptiles. The humanised anti-α-smooth muscle actin (α-SMA) antibody showed intense cross-reactivity in the smooth muscle cells of the hepatic vessels and in the muscle layer of the gallbladder. The portal myofibroblasts, the endothelial cells of the sinusoids and the stromal cells of the cholangiocarcinoma and gallbladder tumours were positive for α-SMA. The antibovine anti-vimentin and humanised anti-Ki-67 antibodies did not show crossreactivity in the different samples from the Bearded dragon.  相似文献   
12.
Development of sorghum hybrids can immensely benefit from an enhanced anther culture protocol since the resultant doubled haploids would accelerate, as in other major cereal crops, the attainment of homozygosity and fixation of alleles. Production of the hybrids that have got high yielding, stress tolerance and other traits of industrial significance in a shorter time as compared to the current trend can hence be realized. This review presents the advances that have been made in the development of such a protocol, with closer attention to androgenic induction components of pre-treatment, culture media composition and conditions as well as ploidy determination and eventual chromosome doubling. From the findings of this review, it is clear that further work is desired to ensure a protocol, that to a large degree, breaks the genotype dependency trend that has been widely cited to impede the usability of the tested protocols.  相似文献   
13.
We investigated the effects of urban environments on the chemical properties of forest soils in the metropolitan areas of Baltimore, New York, and Budapest. We hypothesized that soils in forest patches in each city will exhibit changes in chemistry corresponding to urbanization gradients, but more strongly with various urban metrics than distance to the urban core. Moreover, differences in parent material and development patterns would differentially affect the soil chemical response in each metropolitan area. Results showed that soil chemical properties varied with measures of urban land use in all three cities, including distance to the urban core, which was an unexpected result. Moreover, the results showed that the spatial extent and amount of change was greater in New York than in Baltimore and Budapest for those elements that showed a relationship to the urbanization gradient (Pb, Cu, and to a lesser extent Ca). The spatial relationship of the soil chemical properties to distance varied from city to city. In New York, concentrations of Pb, Cu, and Ca decreased to approximately background concentrations at 75 km from the urban core. By contrast, concentrations of these elements decreased closer to the urban core in Baltimore and Budapest. Moreover, a threshold was reached at about 75% urban land use above which concentrations of Pb and Cu increased by more than twofold relative to concentrations below this threshold. Results of this study suggest that forest soils are responding to urbanization gradients in all three cities, though characteristics of each city (spatial pattern of development, parent material, and pollution sources) influenced the soil chemical response.  相似文献   
14.
15.
The objectives of this study were to investigate the associations between antimicrobial resistance patterns in generic Escherichia coli and Salmonella spp. isolates recovered from identical pen pooled fecal samples, and to evaluate potential clustering of multiple isolates of these organisms within identical fecal samples. Up to 5 generic E. coli (n = 922 isolates) and Salmonella spp. (n = 922 isolates) isolates were obtained from each of 188 pen pooled fecal samples that had been collected from 45 finishing swine farms in Alberta in 2000, and tested for susceptibility to 15 antimicrobials. No isolates of either organism were resistant to 3rd generation cephalosporins or fluoroquinolones, which in Canada are considered antimicrobials of very high importance to human health. Approximately twice as many generic E. coli isolates as Salmonella spp. isolates were resistant to at least 1 antimicrobial. In addition, E. coli isolates showed more multidrug-resistance patterns. No significant association was observed between the resistance phenotypes of Salmonella spp. and E. coli at the fecal sample level. More clustering at the sample level was observed for proportions of antimicrobial resistance (AMR) in Salmonella spp. isolates than E. coli indicating that in future studies it might be sufficient to test fewer than 5 Salmonella spp. isolates per sample.  相似文献   
16.
The recently identified claudins are dominant components of tight junctions, responsible for cell adhesion, polarity and paracellular permeability. Certain claudins have been shown to have relevance in tumour development. The aim of the present study was to analyse the expression of claudin-1, -2, -3, -4, -5, -7 and -10 in normal canine mammary glands. Samples from the inguinal mammary regions of 20 non-castrated, 1-13 years old female dogs were studied. Immunohistochemical analysis was performed on conventional specimens and tissue microarrays. The results of the immunohistochemical reactions detecting claudins in tissue sections were photodocumented. The immunoreactivity of claudins was quantitatively analysed on digital images using Leica QWin morphometry software. Intense membranous immunolabelling was found for claudin-1, -3 and -7, intense membranous with non-granular cytoplasmic immunolabelling for claudin-2, moderate membranous immunolabelling for claudin-4 and -5, and weak membranous immunolabelling for claudin-10. The occurrence of tight junctions was confirmed by ultrathin section electron microscopy. The available data suggested that claudins might be proteins preserved throughout the evolution of mammals. The results of our study support the concept that they are indeed preserved, since the same type of claudins, in identical distribution, could be detected in our canine mammary tissue samples as could be found in human mammary tissue.  相似文献   
17.
Novel analogues of the title compound were prepared in several steps: via addition of methylmagnesium iodide to an acetamide derivative to yield diastereomeric amino alcohols, followed by hydrolysis, cyclization to the corresponding oxazole or thiazole derivative, and a coupling reaction with isocyanates. Results from acaricidal tests showed the compounds to be 100 times less active than hexythiazox. © 1997 SCI.  相似文献   
18.
The Carpathian brook lamprey (Eudontomyzon danfordi Regan, 1911) is an endemic protected species of Cephalaspidomorphi in the Carpathian Basin. No parasites have become known from these jawless vertebrates to date. Here, the authors describe an infection from a single specimen manifesting in protuberant skin cysts 7–10 mm in diameter, scattered on the body surface. Similar dermal infection was observed in 25 of the 274 lampreys recorded in the population survey. Skin cysts filled with round spore-like structures of a dermocystid parasite were found. These particles measured 8–14 µm in diameter and had an about 0.5 µm thick wall, and containing mainly a granular mass and a relatively scarce plasma. No hyphae were recorded. Despite conspicuous morphological changes in the skin, no inflammatory reactions were found. The molecular analysis of 18S rDNA showed similarity to dermocystid species of several fish species but differed from them approximately by 2%. This is the first record of a dermocystid parasite infecting a jawless vertebrate.  相似文献   
19.

Background  

Many established PCR-based approaches in plant molecular biology rely on lengthy and expensive methods for isolation of nucleic acids. Although several rapid DNA isolation protocols are available, they have not been tested for simultaneous RNA isolation for RT-PCR applications. In addition, traditional map-based cloning technologies often use ill-proportioned marker regions even when working with the model plant Arabidopsis thaliana, where the availability of the full genome sequence can now be exploited for the creation of a high-density marker systems.  相似文献   
20.
Staphylococcus sciuri is an occasional cause of human infection that has been described in the flora of numerous animal species and in environmental specimens. Here, we report a rare case of S. sciuri peritonitis in a dialysis patient who had exposure to peridomestic animals.  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