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   10篇
  免费   2篇
综合类   4篇
农作物   1篇
畜牧兽医   5篇
植物保护   2篇
  2020年   1篇
  2018年   1篇
  2017年   1篇
  2015年   1篇
  2014年   1篇
  2013年   1篇
  2012年   1篇
  2009年   2篇
  1997年   2篇
  1989年   1篇
排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
Paleomagnetic measurements indicate that a core dynamo probably existed on the Moon 4.2 billion years ago. However, the subsequent history of the lunar core dynamo is unknown. Here we report paleomagnetic, petrologic, and (40)Ar/(39)Ar thermochronometry measurements on the 3.7-billion-year-old mare basalt sample 10020. This sample contains a high-coercivity magnetization acquired in a stable field of at least ~12 microteslas. These data extend the known lifetime of the lunar dynamo by 500 million years. Such a long-lived lunar dynamo probably required a power source other than thermochemical convection from secular cooling of the lunar interior. The inferred strong intensity of the lunar paleofield presents a challenge to current dynamo theory.  相似文献   
2.
Observations with the High Resolution Imager on the Rontgensatellit reveal x-ray emissions from Jupiter's equatorial latitudes. The observed emissions probably result from the precipitation of energetic (>300 kiloelectron volts per atomic mass unit) sulfur and oxygen ions out of Jupiter's inner radiation belt. Model calculations of the energy deposition by such heavy ion precipitation and of the resulting atmospheric heating rates indicate that this energy source can contribute to the high exospheric temperatures(>800 kelvin at 0.01 microbar) measured by the Galileo probe's Atmospheric Structure Instrument. Low-latitude energetic particle precipitation must therefore be considered, in addition to other proposed mechanisms such as gravity waves and soft electron precipitation, as an important source of heat for Jupiter's thermosphere.  相似文献   
3.
A field grazing trial was undertaken to monitor the health and production of crossbred sheep grazing pasture where Echium plantagineum constituted a considerable proportion of the available forage. The trial, conducted for 19 months over successive grazing seasons, demonstrated a significant difference in production, with sheep on the E. plantagineum pasture being lighter and growing less wool compared with sheep on Echium-free pasture. No mortalities involving pyrrolizidine alkaloid poisoning were recorded in sheep grazing E. plantagineum, although there was histological evidence of moderately severe liver damage associated with high liver copper concentrations in at least one sheep following the grazing of large quantities of the plant.  相似文献   
4.
5.
6.
In this study, mesenchymal stem cells were isolated from rat adipose tissue (AD‐MSCs) to characterize and differentiate them into endothelial‐like cells. AD‐MSCs were isolated by mechanical and enzymatic treatments, and their identity was verified by colony‐forming units (CFU) test and by differentiation into cells of mesodermal lineages. The endothelial differentiation was induced by plating another aliquot of cells in EGM‐2 medium, enriched with specific endothelial growth factors. Five subcultures were performed. The expression of stemness genes (OCT4, SOX2 and NANOG) was investigated. The presence of CD90 and the absence of the CD45 were evaluated by flow cytometry. The endothelial‐like cells were characterized by the evaluation of morphological changes and gene expression analysis for endothelial markers (CD31, CD144, CD146). Characterization of AD‐MSCs showed their ability to form clones, to differentiate in vitro and the OCT‐4, SOX‐2, NANOG genes expression. Immunophenotypic characterization showed the CD90 presence and the CD45 absence. The endothelial‐like cells showed morphological changes, the expression of CD31, CD144, CD146 genes and the presence of CD31 membrane receptor. Matrigel assay showed their ability to form network and vessels‐like structures. This study lays the foundations for future evaluation of the potential AD‐MSCs pro‐angiogenic and therapeutic role.  相似文献   
7.
Journal of Plant Diseases and Protection - In a survey of Botrytis populations in Northern Germany in 2012-2014, an average of 67.7% and 73.8% of isolates from strawberry and raspberry fields...  相似文献   
8.
天然保鲜剂壳聚糖对白桃的保鲜效果   总被引:2,自引:0,他引:2  
为了探讨源东白桃的保鲜技术,以市售壳聚糖保鲜液为原料,进行了常温和4℃条件下源东白桃贮藏保鲜的研究.结果表明,市售壳聚糖保鲜液处理后的白桃失水率、腐烂率明显降低,能抑制可溶性固形物含量的增加,提高总糖的含量,可有效降低果实膜透性.表明,市售壳聚糖是一种安全、高效的天然保鲜剂,可作为常温下贮藏白桃的一种简单有效、安全的方法.  相似文献   
9.
The objective of this study was to evaluate the effects of vitamin C on growth and quality of semen from Oreochromis niloticus breeders. One hundred and sixty males were fed with different levels of vitamin C (0, 261, 599 and 942 mg/kg diet). The higher weight values were recorded for 599 (166 g) and 942 (175 g) mg of vitamin C/kg diet. Sperm motility, vigour and concentration were higher with 599 and 942 mg of vitamin C/kg diet. The semen volume, gonadosomatic index and plasma protein data from the last week showed a direct relationship with increasing levels of vitamin C. No changes were observed in the hepatosomatic index and blood glucose. The haematocrit and erythrocyte showed higher values estimated by equations derived at 850 and 638 mg vitamin C/kg diet, respectively. The leucocytes were inversely proportional to the increasing levels of vitamin C. After 100 days of feeding, animals fed the diet containing 942 mg vitamin C/kg diet had higher sperm motility, linearity, curvilinear velocity, straight line velocity and average path velocity (p < .05). Higher values of beat cross‐frequency were observed in broodfish fed diets containing 942 and 599 mg vitamin C/kg. The different vitamin C levels did not cause differences in straightness, lateral head displacement and sperm morphology. For Nile tilapia males on intensive rearing and handling conditions, vitamin C levels between 599 and 942 mg/kg may be used for a better performance and quality of semen.  相似文献   
10.
HC Lee  WS Jang 《茶叶》2013,(4):528-531
The Da-bu of Hanjae Lee mok (1471-1498) is known as an original masterpiece,which is predominantly documented in Korean tea books.He had always spared no effort to put Confucianists' theories and thoughts into practice during his 28-year career.Da-bu tea magnificently reflected his concepts of Confucianism in conjunction with tea-drinking activities.The main contents of Da-bu have included written authors,tea species and production,landscape of tea cultivation,tea plants and leaves,ways of tea-drinking and three-grade tea,tea song of seven cups,5 merits and 6 moralities of tea,benefits of tea-drinking,tea comprehension,etc.According to the views of contents,tea of Hanjae Leemok is the only partner with which we can share life and it can also be beneficial to healthy diets.Not only does it have become part of our daily life,but also be a medicine for our physical and mental disease.He composed the tea song of seven cups,which sufficiently expressed a real practice of the pursued ideal state of Confucianism and Taoism.He also promoted a drinking tea for health enrichment of Confucianists.According to the analytical results of Da-bu,Hanjae's tea has recognizably become the personally real practice of Confucianism and state.He had reached the enlightenment for the state of birth and death.After consuming tea,his body and mind immediately changed to the state of joys and wonderland,and also he illustrated that this feeling is not a one-off state,it always comes out whenever drinking.Therefore,based on Hanjae Lee mok,tea drinking is not only the regiment for healthy benefits,but also it is a training method," Dado in My Heart",for individuals to train their mind,body,and morality.  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