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   46篇
  免费   3篇
林业   1篇
农学   1篇
  9篇
综合类   9篇
农作物   1篇
水产渔业   5篇
畜牧兽医   20篇
植物保护   3篇
  2023年   1篇
  2021年   1篇
  2020年   3篇
  2019年   3篇
  2018年   1篇
  2017年   2篇
  2015年   2篇
  2014年   3篇
  2013年   1篇
  2012年   4篇
  2011年   5篇
  2010年   1篇
  2009年   1篇
  2008年   2篇
  2007年   2篇
  2006年   7篇
  2005年   5篇
  2004年   2篇
  2003年   1篇
  1998年   1篇
  1982年   1篇
排序方式: 共有49条查询结果,搜索用时 265 毫秒
1.
We have designed a microfluidic device in which we can manipulate, lyse, label, separate, and quantify the protein contents of a single cell using single-molecule fluorescence counting. Generic labeling of proteins is achieved through fluorescent-antibody binding. The use of cylindrical optics enables high-efficiency (approximately 60%) counting of molecules in micrometer-sized channels. We used this microfluidic device to quantify beta2 adrenergic receptors expressed in insect cells (SF9). We also analyzed phycobiliprotein contents in individual cyanobacterial cells (Synechococcus sp. PCC 7942) and observed marked differences in the levels of specific complexes in cell populations that were grown under nitrogen-depleted conditions.  相似文献   
2.
The isolation of broadly neutralizing antibodies against influenza A viruses has been a long-sought goal for therapeutic approaches and vaccine design. Using a single-cell culture method for screening large numbers of human plasma cells, we isolated a neutralizing monoclonal antibody that recognized the hemagglutinin (HA) glycoprotein of all 16 subtypes and neutralized both group 1 and group 2 influenza A viruses. Passive transfer of this antibody conferred protection to mice and ferrets. Complexes with HAs from the group 1 H1 and the group 2 H3 subtypes analyzed by x-ray crystallography showed that the antibody bound to a conserved epitope in the F subdomain. This antibody may be used for passive protection and to inform vaccine design because of its broad specificity and neutralization potency.  相似文献   
3.
Immune-mediated central nervous system inflammation is described in a series of 12 juvenile boxer dogs. A diagnosis of steroid-responsive meningitis-arteritis was made based on the clinical presentation and on diagnostic findings. The boxer breed was at a higher risk for this inflammatory condition than other breeds. Long-term follow-up (>2 years) confirmed a better prognosis in this breed than in the beagle and the Bernese mountain dog. Complete resolution of clinical signs without significant deficits or recurrences was obtained in all cases. Early clinical recognition and immunosuppressive treatment resulted in a better response and complete resolution of the disorder.  相似文献   
4.
5.
Greyhound nonsuppurative meningoencephalitis is an idiopathic breed‐associated fatal meningoencephalitis with lesions usually occurring within the rostral cerebrum. This disorder can only be confirmed by postmortem examination, with a diagnosis based upon the unique topography of inflammatory lesions. Our purpose was to describe the magnetic resonance (MR) imaging features of this disease. Four Greyhounds with confirmed Greyhound nonsuppurative meningoencephalitis were evaluated by MR imaging. Lesions predominantly affected the olfactory lobes and bulbs, frontal, and frontotemporal cortical gray matter, and caudate nuclei bilaterally. Fluid attenuation inversion recovery (FLAIR) and T2 weighted spin‐echo (T2W) sequences were most useful to assess the nature, severity, extension, and topographic pattern of lesions. Lesions were predominantly T2‐hyperintense and T1‐isointense with minimal or absent contrast enhancement.  相似文献   
6.
This study was conducted to compare the effects of shrimp and rabbitfish in mono‐ and polyculture stocked at high biomass on production and environmental conditions in a mesocosm system. Shrimp (14 g) and/or rabbitfish (19 g) were stocked in four treatments with different density but with the same total biomass (236 g m?2), including shrimp monoculture (SM) (17 shrimp m?2), shrimp–fish polyculture (SF) (11 shrimp and 4 rabbitfish m?2), fish–shrimp polyculture (FS) (6 shrimp and 8 rabbitfish m?2) and fish monoculture (FM) (12 rabbitfish m?2). After 10 weeks of experiment, shrimp survival and biomass were low in the treatments where shrimp were dominant (SM, SF), while rabbitfish survival and biomass were high in all the treatments. Shrimp mortality was assumed to be related to an excess of the system carrying capacity (CC). Results suggested that CC is linked to shrimp biomass/density rather than the system eutrophication level. The ecosystem became heterotrophic as daily feed supply was beyond 7 g m?2 per day. This threshold corresponded to the environmental CC of the semi‐intensive shrimp culture system. Under these conditions, the combination of high fish biomass and low shrimp biomass appeared as the most valuable in terms of system performances.  相似文献   
7.
An 8-week feeding trial was carried out to determine the effect of increasing dietary palm oil levels on African catfish juvenile growth and nutrient utilization. Six isonitrogenous diets were formulated to contain 0.5% to 15% crude palm oil with dietary lipid levels ranging from 5% to 20%. Growth performance and protein utilization efficiency of African catfish responded in a positive manner to palm oil addition up to 9% (diet 14% lipid). No further improvement in growth was observed with higher levels of palm oil in the diets, and lower survival was observed with inclusion of 15% palm oil (diet 20% lipid). Whole-body lipid content increased when fish were fed with increasing levels of dietary lipid. Under our experimental conditions, the best growth rate and nutrient utilization were observed with the inclusion of 9% crude palm oil in the diets for African catfish.  相似文献   
8.
Winfried Schröder  Stefan Nickel  Simon Schönrock  Roman Schmalfuß  Werner Wosniok  Michaela Meyer  Harry Harmens  Marina V. Frontasyeva  Renate Alber  Julia Aleksiayenak  Lambe Barandovski  Oleg Blum  Alejo Carballeira  Maria Dam  Helena Danielsson  Ludwig De Temmermann  Anatoly M. Dunaev  Barbara Godzik  Katrin Hoydal  Zvonka Jeran  Gunilla Pihl Karlsson  Pranvera Lazo  Sebastien Leblond  Jussi Lindroos  Siiri Liiv  Sigurður H. Magnússon  Blanka Mankovska  Encarnación Núñez-Olivera  Juha Piispanen  Jarmo Poikolainen  Ion V. Popescu  Flora Qarri  Jesus Miguel Santamaria  Mitja Skudnik  Zdravko Špirić  Trajce Stafilov  Eiliv Steinnes  Claudia Stihi  Ivan Suchara  Lotti Thöni  Hilde Thelle Uggerud  Harald G. Zechmeister 《Annals of Forest Science》2017,74(2):31

Key message

Moss surveys provide spatially dense data on environmental concentrations of heavy metals and nitrogen which, together with other biomonitoring and modelling data, can be used for indicating deposition to terrestrial ecosystems and related effects across time and areas of different spatial extension.

Context

For enhancing the spatial resolution of measuring and mapping atmospheric deposition by technical devices and by modelling, moss is used complementarily as bio-monitor.

Aims

This paper investigated whether nitrogen and heavy metal concentrations derived by biomonitoring of atmospheric deposition are statistically meaningful in terms of compliance with minimum sample size across several spatial levels (objective 1), whether this is also true in terms of geostatistical criteria such as spatial auto-correlation and, by this, estimated values for unsampled locations (objective 2) and whether moss indicates atmospheric deposition in a similar way as modelled deposition, tree foliage and natural surface soil at the European and country level, and whether they indicate site-specific variance due to canopy drip (objective 3).

Methods

Data from modelling and biomonitoring atmospheric deposition were statistically analysed by means of minimum sample size calculation, by geostatistics as well as by bivariate correlation analyses and by multivariate correlation analyses using the Classification and Regression Tree approach and the Random Forests method.

Results

It was found that the compliance of measurements with the minimum sample size varies by spatial scale and element measured. For unsampled locations, estimation could be derived. Statistically significant correlations between concentrations of heavy metals and nitrogen in moss and modelled atmospheric deposition, and concentrations in leaves, needles and soil were found. Significant influence of canopy drip on nitrogen concentration in moss was proven.

Conclusion

Moss surveys should complement modelled atmospheric deposition data as well as other biomonitoring approaches and offer a great potential for various terrestrial monitoring programmes dealing with exposure and effects.
  相似文献   
9.
10.
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