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   245篇
  免费   3篇
  国内免费   3篇
林业   32篇
农学   22篇
基础科学   1篇
  7篇
综合类   113篇
农作物   20篇
畜牧兽医   1篇
园艺   43篇
植物保护   12篇
  2024年   1篇
  2023年   1篇
  2022年   2篇
  2020年   6篇
  2019年   2篇
  2018年   2篇
  2017年   3篇
  2016年   12篇
  2015年   7篇
  2014年   10篇
  2013年   16篇
  2012年   26篇
  2011年   14篇
  2010年   26篇
  2009年   23篇
  2008年   14篇
  2007年   10篇
  2006年   14篇
  2005年   18篇
  2004年   14篇
  2003年   10篇
  2002年   4篇
  2001年   1篇
  2000年   5篇
  1999年   2篇
  1998年   2篇
  1997年   2篇
  1995年   3篇
  1993年   1篇
排序方式: 共有251条查询结果,搜索用时 15 毫秒
51.
蒋桂芝 《热带农业科技》2005,28(3):10-13,34
经一年的田间试验,在西双版纳网棚无土栽培条件下,采用在网棚下增置防雨塑料棚和多种农药组合的6种处理,对幼苗期和产花期细菌性叶疫病表现出有不同程度的防效,但防效较低(10.6%-61.1%), 不能有效抑制病害累计死亡率的快速增长和全部死亡;经研究提出了在现有的栽培条件下,实施“无菌”栽培策略,调整栽培技术思路的建议。  相似文献   
52.
红掌不同品种产生愈伤组织的差异   总被引:7,自引:0,他引:7  
对10个红掌品种2种外植体、4种愈伤组织诱导培养基的组培试验结果:H3、H4、H10、H6、H1等5个品种愈伤组织的平均直径(叶片外植体依次为5.0~3.8mm,叶柄外植体依次为6.6~4.9mm)明显大于H5、H2、H9、H8、H7等5个品种(叶片外植体均为1.0mm,叶柄外植体依次为1.2~2.0mm);叶柄外植体愈伤组织平均直径明显大于叶片外植体;参试培养基B、D产生愈伤组织的直径大于培养基A、C;愈伤组织大的5个品种经增殖、继代培养成完整植株,而愈伤组织小的5个品种愈伤组织在增殖培养中逐渐褐变,全部死亡。  相似文献   
53.
影响红掌愈伤组织诱导、增殖和芽分化的因素   总被引:17,自引:0,他引:17  
以Pink champion等盆栽植株和试管苗为材料,研究了影响红掌愈伤组织诱导、增殖和芽分化的因素。结果表明,不同品种的愈伤组织诱导率和外植体褐变率均存在显著差异,诱导率和褐变率之间呈显著的负相关关系。外植体、外源激素和培养基对愈伤组织的诱导有显著影响,不同品种和外植体的适宜诱导培养基不同。光照对愈伤组织的诱导有显著的抑制作用;高浓度生长素、低浓度细胞分裂素,促进愈伤组织的增殖,高浓度细胞分裂素及低浓度生长素促进愈伤组织芽分化;固体培养比液体培养更有利于愈伤组织的增殖和芽分化。  相似文献   
54.
We tested if salicylic acid (SA) can alleviate chilling injury in anthurium flowers (Anthurium andraeanum). Cut flowers of five cultivars, individually placed in water, were held at 4 °C and 12 °C. Symptoms of chilling injury (CI) were found in the flowers stored at 4 °C. These symptoms included desiccation of the spadix (the compound floral stalk) and a colour change of the spathe (the large floral bract) to pink and then to brown. The time to the CI symptoms depended on the cultivar. CI symptoms were accompanied by an increase in electrolyte leakage, by loss of fresh weight, and by an increase in catalase (CAT) and superoxide dismutase (SOD) activity. SA at 2.0 mM in water was applied as a 15 min dip. It delayed the CI symptoms, as well as the loss of fresh weight, the increase in electrolyte leakage, and the increase CAT and SOD activity. The data suggest that CI in this system is related to an increase in the concentrations of active oxygen species.  相似文献   
55.
阐述在海南岛特有的气候环境条件下,由红掌‘Tropical’试管苗移栽育苗的技术,包括试管苗的移栽育苗质量要求、育苗需要的基本设施条件、育苗的环境条件、移栽育苗的步骤以及育苗管理措施等内容,为海南地区红掌‘Tropical’的育苗提供较全面的指导。  相似文献   
56.
以红掌和春芋2种室内观赏植物以及锦鲤为材料,进行了不同营养液配方对花鱼共养效应的研究,观测供试植株和鱼的生长变化及营养液EC值变化动态。结果表明:1/2倍日本园试营养液浓度最适合红掌生长;霍格兰全营养液配方更有利于春芋的生长,而鱼在低浓度的营养液中更易存活,其生活力随营养液浓度降低而提高。  相似文献   
57.
The aim of this study is to follow each development stage of inflorescence in order to understand the biological feature of flowering and the development of male gametophyte in Anthurium andreanum “Arizona" and to try to find the optimum conditions for its pollination. The methods of dissection and paraffin section were adopted to examine the structural characteristics of anthurium’s tiny floret and the development of the microspore. All the florets of the anthurium arrange on the rhachis helically sub- tended by a colorful bract. Each tiny floret has one gynoecium, four tepals and four stamina. The bract and the florets show different colors during the whole blooming period. The ovary is bicarpellary and has two locules, each of which has one anatropous ovule. The placenta is of a central placentation type. The stylar canal cells not only can produce the secretory mucilage but also can release their own cytoplasm caused by their self-disintegration before the pistil reaches its maturity. The wall of the anther is composed of four layers: epidermis, endothecium, middle layer and tapetum. The tapetal cells and the middle layers’ cells degenerated completely dur- ing meiosis of microsporocytes. The pollen grains were 2-celled at the time of anther dehiscence. Early morning, when the inflores- cences stay at their fifth development stage, is the optimum opportunity for pistil to get pollen grains. The pollen-collection should be done at the end of the seventh stage.  相似文献   
58.
The aim of this study is to follow each development stage of inflorescence in order to understand the biological feature of flowering and the development of male gametophyte in Anthurium andreanum ““Arizona““ and to try to find the optimum conditions for its pollination. The methods of dissection and paraffin section were adopted to examine the structural characteristics of anthurium‘s tiny floret and the development of the microspore. All the florets of the anthurium arrange on the rhachis helically subtended by a colorful bract. Each tiny floret has one gynoecium, four tepals and four stamina. The bract and the florets show different colors during the whole blooming period. The ovary is bicarpellary and has two locules, each of which has one anatropous ovule. The placenta is of a central placentation type. The stylar canal cells not only can produce the secretory mucilage but also can release their own cytoplasm caused by their self-disintegration before the pistil reaches its maturity. The wall of the anther is composed of four layers: epidermis, endothecium, middle layer and tapetum. The tapetal cells and the middle layers‘ cells degenerated completely during meiosis of microsporocytes. The pollen grains were 2-celled at the time of anther dehiscence. Early morning, when the inflorescences stay at their fiRb development stage, is the optimum opportunity for pistil to get pollen grains. The pollen-collection should be done at the end of the seventh stage.  相似文献   
59.
CO2 浓度升高对红掌光合速率与生长发育的影响   总被引:10,自引:1,他引:10  
 本试验以开顶式塑料薄膜温室为设施, 研究了高CO2 浓度对红掌叶片光合速率、植株生长、光合酶活性和花期的影响。结果表明: 处理90 d时, 对照组〔大气CO2 浓度( 360 ±30) μmol·mol- 1 〕红掌的株高、叶面积、株干样质量、株鲜样质量与处理前相比分别增加了16.4%、36.1%、101.2%和84.2% , 而高CO2 浓度组〔( 1 000 ±100 ) μmol·mol- 1 〕则分别增加了72.9%、65.6%、217.6%和199.1%。高CO2 浓度组的净光合速率比对照增加46.27%, 气孔导度下降, 促进了叶片中可溶性糖和淀粉积累, 叶绿素含量比对照下降, 而对Rubisco活性影响较小, 乙醇酸氧化酶活性则明显下降。高CO2 浓度处理50 d时, 开花率为25%, 处理90 d时已达到80%以上, 而在整个试验期间对照组未见开花。因此, 高浓度CO2 处理提高了红掌叶片的光合速率和碳水化合物的积累, 促进了营养生长, 提前了花期。  相似文献   
60.
花烛病虫害     
介绍花烛3种真菌病、3种细菌病、1种线虫病、1种生理病和5种虫害的为害、症状及防治方法。  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