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   212篇
  免费   11篇
林业   9篇
农学   28篇
基础科学   3篇
  59篇
综合类   2篇
农作物   26篇
水产渔业   32篇
畜牧兽医   33篇
园艺   5篇
植物保护   26篇
  2023年   3篇
  2022年   10篇
  2021年   10篇
  2020年   10篇
  2019年   5篇
  2018年   11篇
  2017年   11篇
  2016年   12篇
  2015年   4篇
  2014年   6篇
  2013年   23篇
  2012年   9篇
  2011年   10篇
  2010年   14篇
  2009年   11篇
  2008年   2篇
  2007年   7篇
  2006年   7篇
  2005年   3篇
  2004年   5篇
  2003年   10篇
  2002年   10篇
  2001年   4篇
  2000年   3篇
  1999年   3篇
  1998年   1篇
  1997年   2篇
  1995年   2篇
  1993年   1篇
  1990年   2篇
  1983年   1篇
  1981年   1篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1971年   1篇
  1969年   2篇
  1965年   1篇
排序方式: 共有223条查询结果,搜索用时 0 毫秒
221.
This study investigated the effects of short and prolonged administration of a yeast beta-glucan on non-specific immune parameters, growth rate and the disease resistance of Asian catfish, Clarias batrachus. Fish fed with a basal diet (control) and test diet (basal diet supplemented with 0.1% glucan) for 1, 2 and 3 weeks were assayed for superoxide production, serum myeloperoxidase (MPO) content, natural haemagglutinin level, complement and lysozyme activities. Fish were weighed at weekly intervals and specific growth rate (SGR, % increase in body weight per day) was determined. After each week, fish were challenged with Aeromonas hydrophila to measure the level of protection. Results showed that glucan administration at 0.1% in feed, significantly (P<0.05) enhanced MPO and lysozyme levels, superoxide production, haemagglutination titre and level of protection against A. hydrophila challenge, irrespective of length of exposure. The alternative complement activity and SGR were not affected by the dietary supplementation of yeast glucan. As glucan feeding at 0.1% for 1 week is able to enhance the non-specific immunity and disease resistance of catfish efficiently, short-term feeding might be used in farmed catfish diets to enhance disease resistance.  相似文献   
222.
Polysiphonia morrowii is a well-known red alga that has promising pharmacological characteristics. The current study evaluates the protective effect of 3-bromo-4,5-dihydroxybenzaldehyde (BDB) isolated from P. morrowii on tumor necrosis factor (TNF)-α/interferon (IFN)-γ-stimulated inflammation and skin barrier deterioration in HaCaT keratinocytes. The anti-inflammatory effect of BDB in TNF-α/IFN-γ-stimulated HaCaT keratinocytes is evaluated by investigating nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways, inflammatory cytokines, and chemokines. Further, the interaction between BDB and the skin barrier functions in stimulated HaCaT keratinocytes is investigated. The findings of the study reveal that BDB dose-dependently increases cell viability while decreasing intracellular reactive oxygen species (ROS) production. BDB downregulates the expression of inflammatory cytokines, interleukin (IL)-6, -8, -13, IFN-γ, TNF-α, and chemokines, Eotaxin, macrophage-derived chemokine (MDC), regulated on activation, normal T cells expressed and secreted (RANTES), and thymus and activation-regulated chemokine (TARC) by modulating the MAPK and NF-κB signaling pathways in TNF-α/IFN-γ-stimulated HaCaT keratinocytes. Furthermore, BDB increases the production of skin hydration proteins and tight junction proteins in stimulated HaCaT keratinocytes by preserving skin moisturization and tight junction stability. These findings imply that BDB exhibits a protective ability against inflammation and deterioration of skin barrier via suppressing the expression of inflammatory signaling in TNF-α/IFN-γ-stimulated HaCaT keratinocytes.  相似文献   
223.
Nitrogen (N) supply is the major limiting nutrient in most reclamation schemes. In reclaimed mine soil (RMS), examining the N dynamics can be especially informative for understanding constraints on recovery that restrict revegetation success. Scholarly studies worldwide have focused on exogenous N incorporation to alleviate N shortages in the agriculture, and forestry sectors. Currently, growing concerns for the negative consequences of mining have highlighted N deficiency as one of the most significantly identified abiotic limits. Only a few researchers have focused on the N transformation mechanisms in drastically altered mine soils. The review comprises the last 10 years’ research on mine reclamation approaches using legume and non-legume plant communities. Also the capacity of different amendments to alleviate N shortages in mine soils is emphasized. The major findings of the present review suggest: (i) Revegetation using legume and non-legume species is a self-sustaining and economical alternative to mineral N fertilizer application; however, they cannot fully activate the biological N cycle in RMS. (ii) A more biological amendment-assisted revegetation would enhance the key concepts of “soil-biomass N balance” and would be ideal for N recovery in imbalanced mine soil. Altogether, grass-legume seeding offers a potentially valuable mine reclamation tool for managing N and addressing the challenges of sustainable development.  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