全文获取类型
收费全文 | 140篇 |
免费 | 10篇 |
国内免费 | 12篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 4篇 |
2012年 | 5篇 |
2011年 | 8篇 |
2010年 | 4篇 |
2009年 | 11篇 |
2008年 | 8篇 |
2007年 | 10篇 |
2006年 | 16篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有162条查询结果,搜索用时 234 毫秒
41.
白花龙胆花抗炎作用研究 总被引:1,自引:0,他引:1
为了研究白花龙胆花的抗炎作用,本文对白花龙胆花水提物和70%乙醇提取物的抗炎活性进行了试验,并测定了水提物和70%乙醇提物中龙胆苦苷的含量.试验采用二甲苯所致小鼠急性耳肿胀试验和二甲苯所致小鼠腹部毛细管通透性试验.将昆明种小白鼠分为7组,分别为空白对照组,白花龙胆花水提物高、中、低剂量组和70%乙醇提取物高、中、低剂量组,灌胃(ig)给药14 d后,用二甲苯分别于小鼠右耳及腹部致炎.测定左右耳重量,计算肿胀度及肿胀抑制率,测定吸光值.结果表明:白花龙胆花水提物和乙醇提取物的中、高剂量组对于二甲苯所致的小鼠急性耳肿胀和小鼠腹部毛细管通透性都有显著的抑制作用.从而表明:白花龙胆花具有显著的抗炎疗效. 相似文献
42.
43.
44.
Three undescribed glycoside constituents, macrophyllosides E-G and a pair of iridoid glycosides genticrasides A/B, together with eleven known glycoside compounds were isolated from the roots of Gentiana crassicaulis Duthie ex Burk. Their structures were identified by means of spectra analysis and data comparison with previous literatures. Interestingly, the glucose moieties in macrophylloside E and F possess free anomeric hydroxy groups. Genticrasides A/B, identified as a pair of iridoid originated lactones, have not been reported from Gentianaceae family up to now. The anti-inflammatory effects of selected compounds were also evaluated through the nitric oxide (NO) production inhibition in lipopolysaccharides (LPS)-induced RAW264.7 macrophage cells. In which, macrophyllosides G and D showed NO inhibitory activities with rates of 76.14±4.02 % and 52.44±8.29 % at 100 μg/mL. 相似文献
45.
Christiane Meyer-Hozak 《Journal of Insect Conservation》2000,4(2):63-72
The population biology of Maculinea rebeli Hirschke, 1904, on dry grassland biotypes in different successional stages was investigated in the summers of 1990 and 1991 in the district of Höxter (North Rhine–Westphalia, Germany). The population characteristics of M. rebeli were studied by mark-recapture and eggshell counts on the larval host plant Gentiana cruciata. Pitfall traps, ant baits, excavating and counting of ant nests were used to examine the Formicidae community and the nest density of Myrmica sabuleti. In 1990, the total population of M. rebeli was estimated as 528 individuals, with subpopulations varying from 2 to 273 individuals. Populations existed in areas differing in size and vegetation structure. However, the limiting factor for population size was the density of the host ant population. The differences in population size did not depend on the size of the habitat or the density of the larval food plant. The butterflies can switch their host. In the absence of M. schenki, the colonies of M. sabuleti can maintain M. rebeli populations. Adult males and females have a maximum life expectancy of 13 days. The females prefer to oviposit on G. cruciata plants of 10–30cm height. Only plants which stuck out of the surrounding vegetation were oviposited on. The average number of eggs deposited per female was 100–150. Low density populations are probably most threatened. Therefore, future protective measures should work towards further maintaining and optimizing the habitats of the small populations, as well as creating the prerequisites so that dense stable populations of M. rebeli can develop. 相似文献
46.
Anna?Miku?aEmail author Teresa?Tykarska Mieczys?aw?Kura? Jan?J.?Rybczyński 《In vitro cellular & developmental biology. Plant》2005,41(5):686-694
Summary Structure and ultrastructure changes that occurred during tissue culture of upper explants of hypocotyl (adjacent to cotyledons)
of 10-d-old seedlings of Gentiana cruciata were studied. The explants were cultured on Murashige and Skoog induction medium supplemented with 1.0 mg l−1 dicamba +0.1 mg l−1 naphthaleneacetic acid +2.0 mg l−1 benzyladenine +80.0 mg l−1 adenine sulfate. The initial response of the explant and callus formation were ultrastructurally analyzed during the first
11 d of culture. After 6–8 wk, various methods were employed to collect evidence of indirect somatic embryogenesis. After
48 h of culture, the earliest cell response was cell division of epidermis and primary cortex. There were numerous disturbances
of karyo- and cytokinesis, leading to formation of multinuclear cells. With time, the divisions ceased, and cortex cells underwent
strong expansion, vacuolization and degradation. About the 6th day of culture, callus tissue proliferated and the initial
divisions of vascular cylinder cells were observed. Their division appeared normal. Cells originating from that tissue were
small, weakly vacuolated, with dense cytoplasm containing active-looking cell organelles. Numerous divisions occurred in the
vascular cylinder, which led to its expansion and the formation of embryogenic callus tissue. During the 6–8th wk of culture,
in the proximal end of the explant, masses of somatic embryos were formed from outer parts of intensively proliferating tissue. 相似文献
47.
Isolation of iridoid and secoiridoid glycosides and comparative study on Radix gentianae and related adulterants by HPLC analysis 总被引:5,自引:0,他引:5
HPLC profile guided study led to the isolation of an acylated secoiridoid glycoside, named gentiotrifloroside (1), together with six known compounds, i.e., loganic acid (2), 6-O-beta-d-glucopyranosylgentiopicroside (3), swertiamarin (4), gentiopicroside (5), sweroside (6) and 2 -(o,m-dihydroxybenzyl)-sweroside (7) from Gentiana triflora and Gentiana rigescens. The structure of 1 was deduced from one- and two-dimensional NMR spectroscopic experiments. Compounds 1-7 were used successfully as chemical markers for the comparison of the four species of Gentiana used as Radix gentianae. Additionally, differentiation of Gentiana species mentioned and those used as adulterants was evaluated. The close similarity of chemical composition among the four genuine Gentiana species explain their popular usage as R. gentianae in Chinese medicine. We have also shown that the variation of chemical composition in R. gentianae and related adulterants agree well with their botanical phylogeny. 相似文献
48.
Gentiana rhodantha Franch. ex Hemsl. (Gentianaceae), an annual herb widely distributed in the southwest of China, has been medicinally used for the treatment of inflammation, cholecystitis, and tuberculosis by the local people of its growing areas. Chemical investigation on the whole plants led to the identification of eight new phenolic compounds, rhodanthenones A–D ( 1 – 4 , resp.), apigenin 7‐O‐glucopyranosyl‐(1→3)‐glucopyranosyl‐(1→3)‐glucopyranoside ( 5 ), 1,2‐dihydroxy‐4‐methoxybenzene 1‐O‐α‐L ‐rhamnopyranosyl‐(1→6)‐β‐D ‐glucopyranoside ( 6 ), 1,2‐dihydroxy‐4,6‐dimethoxybenzene 1‐O‐α‐L ‐rhamnopyranosyl‐(1→6)‐β‐D ‐glucopyranoside ( 7 ), and methyl 2‐O‐β‐D ‐glucopyranosyl‐2,4,6‐trihydroxybenzoate ( 8 ), together with eleven known compounds, 9 – 19 . Their structures were determined on the basis of detailed spectroscopic analyses and chemical methods. Acetylcholinesterase (AChE) inhibition and cytotoxicity tests against five human cancer cell lines showed that only rhodanthenone D ( 4 ) and mangiferin ( 12 ) exhibited 18.4 and 13.4% of AChE inhibitory effects at a concentration of 10−4 M , respectively, while compounds 1 – 5 and the known xanthones lancerin ( 11 ), mangiferin ( 12 ), and neomangiferin ( 13 ) displayed no cytotoxicity at a concentration of 40 μM . 相似文献
49.
Protoplasts were isolated from cell suspensions derived from cotyledon and hypocotyl Gentiana kurroo (Royle). Cell walls were digested with an enzyme cocktail containing cellulase, macerozyme, driselase, hemicellulase and
pectolyase in CPW solution. Protoplast viability ranged from 88 to 96%. Three techniques of culture and six media were evaluated
in terms of their efficiency in producing viable cultures and regenerating whole plants. With liquid culture, cell division
occurred in only a low number of the protoplasts isolated, and no plant regeneration was successful. Cell division occurred
within 2 or 3 days in case of agarose solidified media. After 10 days of culture, the number of dividing cells was the highest
with modified MS medium in which NH4NO3 was replaced with 3.0 g l−1 glutamine. The best results were obtained with agarose bead cultures: plating efficiency was 68.7% and 58.1% for protoplasts
isolated from cotyledon and hypocotyl derived suspensions, respectively. The results were achieved with using medium containing
0.5 mg l−1 2,4-D + 1.0 mg l−1 kinetin or 2.0 mg l−1 BAP + 1.0 mg l−1 dicamba + 0.1 mg l−1 NAA + 80 mg l−1 adenine sulfate. Protocalluses transferred on the following composition of plant growth regulators: 0.5 mg l−1 2,4-D + 1.0 mg l−1 kinetin or 1.0 mg l−1 kinetin + 0.5 mg l−1 GA3 + 80.0 mg l−1 adenine sulfate developed in embryogenic cultures. However, the best embryo production occurred with the first one. Later
embryos were transferred to half-strength MS mineral salts to promote plants formation. Flow cytometry studies revealed increased
amounts of DNA in about one third of the regenerants. 相似文献
50.
用nrDNA ITS序列探讨狭蕊龙胆属及其近缘属 (龙胆科)的系统发育 总被引:2,自引:0,他引:2
运用核糖体DNA内转录间隔区ITS序列对狭蕊龙胆属Metagentiana10种及其近缘属22种植物进行了系统发育分析。ITS分析结果表明狭蕊龙胆属是一个多系群:在系统发育树上,双蝴蝶属Tripterospermum和蔓龙胆属Crawfurdia的种类位于狭蕊龙胆属各分支中,而且双蝴蝶属和蔓龙胆属的种类也相互交叉;这一结果不支持将3个属各自独立为属。但是,在所有分析中,3个属共同形成一单系分支,是龙胆属Gentiana的姊妹群;这一结果与形态学、花部解剖学、细胞学、孢粉学和胚胎学等证据基本一致,狭蕊龙胆属应该从龙胆属中分离出来,它与双蝴蝶属和蔓龙胆属有更为密切的亲缘关系。根据分支图,在狭蕊龙胆属、双蝴蝶属和蔓龙胆属组成的复合群中,现已知的染色体基数x=17、21和23可能存在网状和平行进化。 相似文献