全文获取类型
收费全文 | 141篇 |
免费 | 6篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 22篇 |
2012年 | 13篇 |
2011年 | 9篇 |
2010年 | 10篇 |
2009年 | 2篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有147条查询结果,搜索用时 15 毫秒
61.
Antioxidant constituents of Nymphaea caerulea flowers 总被引:1,自引:0,他引:1
As part of an ongoing search for antioxidants from medicinal plants, 20 constituents were isolated from the Nymphaea caerulea flowers, including two 2S,3S,4S-trihydroxypentanoic acid (1), and myricetin 3-O-(3'-O-acetyl)-alpha-L-rhamnoside (2), along with the known myricetin 3-O-alpha-L-rhamnoside (3), myricetin 3-O-beta-D-glucoside (4), quercetin 3-O-(3'-O-acetyl)-alpha-L-rhamnoside (5), quercetin 3-O-alpha-L-rhamnoside (6), quercetin 3-O-beta-D-glucoside (7), kaempferol 3-O-(3'-O-acetyl)-alpha-L-rhamnoside (8), kaempferol 3-O-beta-D-glucoside (9), naringenin (10), (S)-naringenin 5-O-beta-D-glucoside (11), isosalipurposide (12), beta-sitosterol (13), beta-sitosterol palmitate (14), 24-methylenecholesterol palmitate (15), 4alpha-methyl-5alpha-ergosta-7,24(28)-diene-3beta,4beta-diol (16), ethyl gallate (17), gallic acid (18), p-coumaric acid (19), and 4-methoxybenzoic acid (20). The structures were determined by spectroscopic means. Compounds were tested for antioxidant activity and nine compounds 2-7, 11, 12 and 18 were considered active with IC(50) of 1.16, 4.1, 0.75, 1.7, 1.0, 0.34, 11.0, 1.7 and 0.95 microg/ml, respectively, while 1 was marginally active (IC(50)>31.25 microg/ml). The most promising activity was found in the EtOAc fraction (IC(50) 0.2 microg/ml). This can be attributed to the synergistic effect of the compounds present in it. 相似文献
62.
The nutritional role of silver for the freshwater crustacean, Daphnia magna, was examined through four generations of deprivation. Silver inclusion in animal media was set at a nominal zero (employing
chemicals of the highest available purity). Both reproduction (−60%) and life span (−40%) were negatively affected when compared
to animals reared in the presence of 0.4 ng g−1 Ag. These results strongly suggest a nutritional requirement of silver for daphnids at nanomolar concentrations. 相似文献
63.
64.
65.
Xian-Fu Fang Di Li Vijai Kumar Reddy Tangadanchu Lavanya Gopala Wei-Wei Gao Cheng-He Zhou 《Bioorganic & medicinal chemistry letters》2017,27(22):4964-4969
A series of novel potentially antifungal hybrids of 5-flucytosine and fluconazole were designed, synthesized and characterized by 1H NMR, 13C NMR, IR and HRMS spectra. Bioactive assay manifested that some prepared compounds showed moderate to good antifungal activities in comparison with fluconazole and 5-flucytosine. Remarkably, the 3,4-dichlorobenzyl hybrid 7h could inhibit the growth of C. albicans ATCC 90023 and clinical resistant strain C. albicans with MIC values of 0.008 and 0.02?mM, respectively. The active molecule 7h could not only rapidly kill C. albicans but also efficiently permeate membrane of C. albicans. Molecular docking study revealed that compound 7h could interact with the active site of CACYP51 through hydrogen bond. Quantum chemical studies were also performed to explain the high antifungal activity. Further preliminary mechanism research suggested that molecule 7h could intercalate into calf thymus DNA to form a steady supramolecular complex, which might block DNA replication to exert the powerful bioactivities. 相似文献
66.
The preservative systems of unused, anhydrous mascaras were challenged periodically with microorganisms, using a modified membrane procedure. Shelf life of preservative activity against Pseudomonas aeruginosa varied for different brands from as little as 1 month to over 36 months. Generally, P. aeruginosa grew in mascaras after the mascaras were challenged first with Staphylococcus epidermidis or Candida albicans. 相似文献
67.
The structure of 3, 21, 24 trimethyl-5,7-dihydroxyhentriacontanoic acid δ-lactone, a new δ-lactone, isolated from the flowers of Grewia asiatica has been deduced on the basis of physico-chemical studies. 相似文献
68.
Vijai Lakshmi Dhan Prakash Kanwal Raj Randhir S. Kapil Satya P. Popli 《Phytochemistry》1984,23(11):2629-2631
A reinvestigation of Clausena anisata has yielded imperatorin, xanthotoxol, lansamide-I and three new furanocoumarin lactone derivatives: indicolactone, anisolactone and 2′,3′-epoxyanisolactone. The structures of these compounds have been elucidated by a combination of spectroscopic and chemical methods. 相似文献
69.
Phthalimide treatments at 125, 250 and 500 mg 1–1 to female plants of dioecious Morus nigra L. induced intersex and male flowers. Qualitative and quantitative analyses of acid phosphatase in male and female flower buds showed that the male flower had significantly higher levels of the enzyme activity than the female flower buds. The level of acid phosphatase activity significantly increased in intersex and male flowers induced on female plants after phthalimide treatments. 相似文献
70.