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   251篇
  免费   13篇
林业   19篇
农学   12篇
基础科学   2篇
  72篇
综合类   14篇
农作物   50篇
水产渔业   23篇
畜牧兽医   41篇
园艺   5篇
植物保护   26篇
  2023年   3篇
  2022年   12篇
  2021年   23篇
  2020年   14篇
  2019年   14篇
  2018年   24篇
  2017年   16篇
  2016年   17篇
  2015年   7篇
  2014年   15篇
  2013年   28篇
  2012年   13篇
  2011年   17篇
  2010年   9篇
  2009年   9篇
  2008年   13篇
  2007年   8篇
  2006年   5篇
  2005年   6篇
  2004年   3篇
  2003年   2篇
  2002年   1篇
  2001年   1篇
  1999年   1篇
  1998年   1篇
  1994年   1篇
  1988年   1篇
排序方式: 共有264条查询结果,搜索用时 15 毫秒
261.
The possibility of preparing olive oil, with the same nutritional value and stability characteristics found in virgin olive oil, by the enrichment of refined olive oil with olive leaf polyphenols was studied. To obtain antioxidant phenols similar to those found in virgin olive oil, these components were extracted from the leaves of several olive cultivars from the Northern region of Portugal, namely, Carrasca, Ripa, Negruche, Cordovil, Verdeal, Madural, and Bical cultivars, under several conditions. The concentration of a leaf extract required for addition to refined olive oil to obtain the same stability as virgin olive oil was determined. The extract from 1 kg of leaves was sufficient to fortify 50-320 L of refined olive oil to a similar stability as a virgin olive oil sample depending on the metal concentration of the oil, cultivar, and time of the year when the leaves were picked.  相似文献   
262.
Reproduction efficacy of sturgeon as donors of oocytes is regulated by hormones effects. It can influence the egg quality or larvae functions as rearing mediators for successful production. This study is conducted to evaluate the concentration of sex steroids, cortisol and thyroid hormones and distinguish the relationship of maternal hormones' correlation in Stellate sturgeon. The study followed the hormones fluctuations that could impress some egg quality information such as fertilization rate. Female breeders were injected with LHRHa2 for controlled propagation. Samples from blood, ovarian fluid and oocytes were obtained for hormonal and biochemical analysis. Our results showed that the concentrations of estradiol 17‐β and testosterone were significantly higher and lower in oocyte and the plasma, respectively. The level of plasma cortisol was significantly higher than in ovarian fluid and oocytes. The results showed elevation of triiodothyronine and thyroxine concentrations in oocytes, which were significantly different with plasma and ovarian fluid. Thyroxine concentration of plasma and ovarian fluid revealed a significant negative correlation. The mentioned parameters showed negative correlation with fertilization rate. The biochemical parameters (calcium, glucose, cholesterol and triglyceride) revealed significant differences in blood, ovarian fluid and oocytes. These results showed direct relations of fertilization rate with hormones level. Therefore, fertilization rate as egg quality index could be recommended as a relevant indicator of maternal transferring of hormones from blood and ovarian fluid to oocyte.  相似文献   
263.
In September 2017, an outbreak with high mortality, which showed the typical signs of ND, occurred among a flock of more than 2000 Eurasian collared doves in Konarak, southeast of Iran. A confirmed pigeon paramyxovirus type 1 strain was isolated from the brain tissues of the dead doves. The isolate, which was called Pigeon/Iran/Konarak/Barin/2017, was classified as a highly velogenic NDV. Complete genome sequencing and phylogenetic analysis showed that the isolate belonged to subgenotype XXI.2, which has never been reported from Iran before. The isolate had the highest homology (96.15%) with early 2010s Italian isolates. Further studies will be required to understand the diversity better.  相似文献   
264.
Chemosensory proteins(CSPs) are important molecular components of the insect olfactory system, which are involved in capturing, binding, and transporting hydrophobic odour molecules across the sensillum in sensillar lymph in regulating insect behavior. This protein family(CSPs) is also involved in many other systems that are not linked to olfactory receptors in olfactory sensilla. The brown planthopper(BPH) is a monophagous pest of rice that causes damage by sucking phloem sap and transmitting a...  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