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   14篇
  免费   0篇
  国内免费   5篇
化学   17篇
综合类   2篇
  2018年   1篇
  2011年   2篇
  2010年   1篇
  2009年   1篇
  2008年   2篇
  2006年   1篇
  2004年   3篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1995年   2篇
  1994年   2篇
  1988年   1篇
排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
近江牡蛎受精细胞学研究   总被引:5,自引:0,他引:5  
用醋酸──地衣红染色的方法对近江牡蛎人工授精的卵子减数分裂和受精过程进行了详细的细胞学观察.精子入卵前,卵子处于第一次减数分裂的前期(胚泡期),精子入卵后,胚泡消失,然后进行两次减数分裂,在海水温度为28.8℃的情况下,授精后33min和45min,绝大部分受精卵已排出第一极体和第二极体,雄原核可在第一极体排出后及第二极体排出前任何时期内形成,雌雄原核以联合的方式将两组染色体合并,授精后1h,大部分卵子完成第一次卵裂.在25℃和26℃授精的情况下,观察到了较多的多精入卵的现象.卵子发育的非同步性现象非常明显.  相似文献   
2.
两头尖化学成分研究   总被引:6,自引:0,他引:6  
通过硅胶柱色谱、大孔树脂、反相柱层析及半制备型高效液相色谱等方法,从两头尖根茎中分离得到3种化合物,根据理化性质和光谱分析(ESI-MS、^1HNMR、^13CNMR、HMBC、HMQC、TOCSY、DEFT)鉴定其结构分别为:3-O-α-L-吡喃鼠李糖基-(1→2)-[β-D-吡喃葡萄糖基-(1→4)]-α-L-吡喃阿拉伯糖基齐墩果酸28-β-D-吡喃葡萄糖基-(1→6)-β-D.吡喃葡萄糖酯(I)、3-O-α-L吡喃阿拉伯糖基-(1→3)-O-α-L吡喃鼠李糖基-(1→2)-α-L-吡喃阿拉伯糖基齐墩果酸28-α-L吡喃鼠李糖基-(1→4)-β-D-吡喃葡萄糖基-(1→6)-β-D-吡喃葡萄糖酯㈣和3-O-α-L-吡喃鼠李糖基-(1→9)-α-L-吡喃阿拉伯糖基齐墩果酸28-α-L-吡喃鼠李糖-(1→4)-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯(Ⅲ),其中化合物Ⅰ、Ⅱ为新化合物,分别命名为多被银莲花皂苷14(Rad-deanoside 14),多被银莲花皂苷15(Raddeanoside 15)。化合物Ⅲ为已知化合物常春藤皂苷B。  相似文献   
3.
两头尖的化学成分研究(Ⅱ)   总被引:3,自引:0,他引:3  
两头尖系毛莨科银莲花属植物多被银莲花(Anemone raddeanaRegel)的干燥根茎,分布于我国东北及山东等地.其味辛性热,具有祛风湿、消痈肿之功效.其总皂苷具有显著的抗肿瘤、抗炎、镇痛、镇静及抗惊厥作用.近年来,国内学者对其化学成分进行了较深入研究,已分离出近20种三萜皂苷类成分以及多种挥发油和多糖类成分.我们从两头尖中分离并鉴定了3个双糖链三萜皂苷化合物,其中化合物1为新化合物.化合物2和3为首次从两头尖中获得的已知化合物.  相似文献   
4.
A New Triterpenoid Saponin from Anemone tomentosa   总被引:2,自引:0,他引:2  
TherootsofAnemonetomentosa(Maxim.)PeiareusedasafolkmedicineforthetreatmentofdysenteriainChinal.Recently,twonewcoumarinsandnineknowncompoundswereisolatedfromtheethylacetateeXtractwhichexhibitedstrongantifeedantactivityagainstLeucaniaSeparataWailiee.Duringthefurtherinvestigationofthetitleplant,anewminorsaponin,tomentoside,togetherwithfourknownoneswasisolated.Tomentoside(5),amorphouspowder,[a]D-41.5(MeOH,c0.26).MolecularformulawasdeterminedasC,,H,,.O,.byHRFABMS,m/zf1497.7166([M-H]-),caf…  相似文献   
5.
A new triterpenoid saponin, 3-O-[(6′-butyryl)-β-D-glucopyranosyl]-28-O-[α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl] oleanolic acid, as well as three known triterpenoid saponins were isolated from the rhizomes of Anemone flaccida. Their structures were elucidated by spectroscopic methods. These compounds showed significant antitumor activities.  相似文献   
6.
草玉梅中的化学成分   总被引:6,自引:0,他引:6  
从草玉梅根部和地上部分甲醇提取物中分离到的8个化合物,其中三萜内酯(7)和三萜皂甙(8)为新化合物.  相似文献   
7.
建立了电喷雾多级质谱结合硅胶柱层析快速、全面分析中药两头尖中三萜皂苷成分的方法.取两头尖粉末30 g,在60℃下以300 mL 70%甲醇溶液提取6次,合并提取液,减压浓缩得提取物3.3 g,提取物悬浮于20mL,水中,先用乙酸乙酯(20 mL×3)萃取除脂,再用正丁醇(20 mL×6)萃取.取正丁醇萃取物1.5 g进...  相似文献   
8.
Two new oleanolic acid‐type triterpenoid saponins, raddeanosides R22 and R23 ( 1 and 2 , resp.), together with four known saponins were isolated from the rhizome of Anemone raddeana Regel. The structures of the new compounds were elucidated as oleanolic acid 3‐Oβ‐D ‐glucopyranosyl(1→2)[β‐D ‐glucopyranosyl(1→4)]‐α‐L ‐arabinopyranoside ( 1 ) and oleanolic acid 3‐Oα‐L ‐arabinopyranosyl(1→3)‐α‐L ‐rhamnopyranosyl(1→2)[β‐D ‐glucopyranosyl(1→4)]‐α‐L ‐arabinopyranoside ( 2 ). The four known compounds were identified as oleanolic acid 3‐Oα‐L ‐arabinopyranoside ( 3 ), oleanolic acid 3‐Oβ‐D ‐glucopyranosyl(1→4)‐α‐L ‐arabinopyranoside ( 4 ), hederasaponin B ( 5 ), and hederacholchiside E ( 6 ) on the basis of chemical and spectral evidences. Compound 4 is reported for the first time from the Anemone genus, while the other three known compounds have been already found in this plant.  相似文献   
9.
Two new natural products, i.e., 1‐O,2‐O‐[(1S,2S)‐1‐(3‐acetyl‐2,4,6‐trihydroxyphenyl)‐3‐hydroxypropane‐1,3‐diyl]‐β‐D ‐glucopyranose (=tomentoside I; 1 ) and (3β)‐3‐(acetyloxy)ferruginol 12‐[6‐O‐(4‐hydroxy‐3,5‐dimethoxybenzoyl)‐β‐D ‐glucopyranoside] (=tomentoside II; 2 ), were isolated from the EtOH extract of the root of Anemone tomentosa, together with five known compounds. Their structures were characterized by means of spectroscopic methods, especially by 1H‐, 13C‐, and 2D‐NMR and HR‐MS, as well as by chemical methods and comparison with literature data.  相似文献   
10.
A new triterpenoid saponins, raddeanoside R19 (1) was isolated from the rhizome of Anemone raddeana Regel. The effects of raddeanoside R19 on superoxide generation in human neutrophil were evaluated. The compound suppressed the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol 12-myristate 13-acetate (PMA) and araehidonic acid (AA) in a different concentration-dependent manner.  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