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   52篇
  免费   2篇
化学   18篇
综合类   36篇
  2022年   4篇
  2021年   7篇
  2020年   3篇
  2019年   1篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   3篇
  2014年   2篇
  2013年   1篇
  2012年   1篇
  2011年   2篇
  2010年   3篇
  2008年   1篇
  2007年   4篇
  2006年   2篇
  2005年   2篇
  2004年   5篇
  2003年   1篇
  2001年   1篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1996年   1篇
  1993年   2篇
  1990年   1篇
排序方式: 共有54条查询结果,搜索用时 741 毫秒
1.
桂花品种研究   总被引:8,自引:0,他引:8  
在对桂花的研究历史、木犀属及桂花的地理分布深入分析的基础上,对全国范围内的桂花品种进行了系统的分类整理,共统计157个品种,分属于4大品种群,规范了各级分类单位的命名。  相似文献   
2.
桂花新品种   总被引:1,自引:1,他引:1  
在系统调查我国桂花品种的基础上,对37个新品种(四季桂品种群6个、银桂品种群11个、金桂品种群7个、丹桂品种群13个)进行了描述。  相似文献   
3.
对安徽省桂花品种进行了调查,共记载36个品种,分别属于4个品种群,其中金桂品种群13个品种,银桂品种群10个品种,丹桂品种群8个品种,四季桂品种群5个品种。同时,编制了各品种群的品种分类检索表,并对各品种特征进行了详细的描述。  相似文献   
4.
怀地黄不同品种根部特征和有效成分含量比较   总被引:4,自引:1,他引:3  
以怀地黄6个栽培品种为材料,初步探讨了怀地黄不同品种的根部性状和品质性状.在相同的栽培条件下,测量了怀地黄6个主流栽培品种的块根外观性状,利用石蜡切片法观察并测量不同品种块根的解剖结构,微量元素和梓醇含量的测定分别用荧光光度计和高效液相色谱法.结果表明怀地黄不同品种梓醇含量、单株块根鲜重和块根中木质部的面积都有明显差异,梓醇含量和块根中木质部的比例呈显著正相关.  相似文献   
5.
对三种栽培品种芍药的核型进行了比较研究,和野生种芍药的核型相比,除有一对同源染色体上均有随体这一特点外,其余特征和相应野生种相似。  相似文献   
6.
对5个大白菜品种在4个试验点进行田间试验,重点比较了品种81—5和青杂3号的农艺、品质性状和抗病、抗冻能力。品种81—5苗期生长势、成株紧实度、单株重及亩产量几项性状均明显优越;品质性状总体上看也比较好,表现是含水量和纤维素含量低、蛋白质总量和维生素C及糖分含量高,但游离氨基酸和人体必需的8种蛋白质氨基酸含量较低;对软腐病等主要病害的抗性、耐贮性和抗冻能力均较强,原生质体对冻害损伤的抵抗力较品种青杂3号高40%以上。  相似文献   
7.
Olea europaea germplasm is constituted by a huge number of cultivars, each one characterized by specific features. In this context, endemic cultivars evolved for a very long period in a precise local area, developing very specific traits. These characteristics include the production and accumulation of phytochemicals, many of which are also responsible for the nutraceutical value of the drupes and of the oils therefrom. With the aim of obtaining information on the phytochemical profile of drupes of autochthonous cultivars of Cilento, Vallo di Diano and Alburni National Park, a metabolomics-based study was carried out on 19 selected cultivars. Multivariate data analysis of 1H-NMR data and 2D NMR analyses allowed the rapid identification of metabolites that were qualitatively and/or quantitatively varying among the cultivars. This study allowed to identify the cultivars Racioppella, Guglia, Pizzulella, Oliva amara, and Racioppa as the richest in health-promoting phenolic compounds. Furthermore, it showed a significant variability among the different cultivars, suggesting the possibility of using metabolic fingerprinting approaches for cultivar differentiation, once that further studies aimed at assessing the influence of growing conditions and environmental factors on the chemical profiles of single cultivars are carried out.  相似文献   
8.
董汉松  曲建军 《山东科学》1993,6(2):36-42,56
文章首先测验了3种培养液对烟苗生长的影响和赤星病菌在培养液中产生毒素的能力,据此选出查彼培养液用于产生毒素的培养。病菌在查彼培养液中生长28天后,表现出最高的毒素活性,毒素活性临界值(TWE50)为32。然后用毒素粗提液处理幼苗,以幼苗悬滴接种法为对比。烟苗在12小时内可见对毒素发生明显反应,表现为根部变褐和须根脱落,对悬滴接种的反应要到72小时后才可鉴别。毒素处理后36小时内烟苗进而萎蔫,21个品种的萎蔫程度与12小时内的根部反应趋势一致,根部反应和萎蔫的程度又同时与品种对悬滴接种的反应趋势相一致,3种反应间的吻合度平均近80%。  相似文献   
9.
A range of conventional, i.e. maceration, percolation, ultrasonic assisted, Soxhlet and Soxtec extraction (STE), to advanced extraction techniques of accelerated solvent extraction (ASE) was utilized for the first time in order to optimize the extract yield and recovery of phenolics—gallic acid (GA), rutin (RT) and quercetin (QT)—quantified via ultra-high performance liquid chromatography with diode array detector (UHPLC–DAD). The effect of solvents (n-hexane, dichloromethane and methanol) and temperature (60, 80 and 100°C) upon extraction yield, phenolic content and antioxidant activity (DPPH, ABTS and DPPH) was studied, and the method was validated in commercial food samples from Saudi Arabia, China and India. A high extract yield with percentage recovery was observed for STE (1221.10 mg/5 g; 24.42%) and ASE techniques (91.50 mg/1 g; 9.15%) in methanol at 100°C. UHPLC–DAD showed retention times (min) of 0.67, 1.93 and 1.90 for GA, RT and QT, respectively in the shortest runtime of 3 min. The yield for phenolics was higher for STE/ASE (ppm): 15.27/15.29 (GA), 85.24/37.56 (RT) and 52.20/33.40 (QT), respectively. In terms of antioxidant activities, low IC50 values (μg/ml) of 1.09/1.18 (DPPH), 2.11/5.32 (ABTS) and 4.35/7.88 (phenazine methosulfate–nicotinamide adenine dinucleotide) were observed for STE and ASE, respectively. Multivariate analysis for STE showed a significant (P = 0.000) correlation for extraction type vs. extract yield and phenolics content; however, there was no significance for antioxidant activities vs. extraction type. ASE showed a positive correlation for solvent vs. extraction yield, phenolics and antioxidant activity; however, there was no correlation for extraction yield and DPPH activity. Principal component analysis for STE showed a major variability (52.02%) for extraction yield and phenolics in PC1 followed by PC2 (38.30%) for antioxidant activities. For ASE, PC1 (48.68%) showed a positive correlation for solvent vs. extraction yield and phenolics while PC2 (33.12%) showed a positive correlation for temperature and antioxidant activities. STE and ASE were the optimized extraction techniques for the garlic food sample while a significant effect of solvent and temperature was observed upon extraction yield, phenolics and antioxidant activity.  相似文献   
10.
樱花新品种     
在系统调查我国樱属品种资源的基础上,按观赏形态特征,依据《国际栽培植物命名法规》(ICNCP)的规定,报道了17个樱属新品种,分属于7个种,1个变种,并对其特征进行了描述。  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