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1.
New macrolactins from a marine Bacillus sp. Sc026   总被引:6,自引:0,他引:6  
Bioassay-guided fractionation of the EtOAc extract of a marine Bacillus sp. Sc026 culture broth has led to the isolation of the known compound, macrolactin F (1), together with two new compounds, 7-O-succinyl macrolactin F (2) and 7-O-succinyl macrolactin A (3). The chemical structures of 1-3 were elucidated on the basis of spectral data analyses and literature data comparison. Compounds 1-3 exhibited antibacterial activity against Bacillus subtilis and Staphylococcus aureus.  相似文献
2.
The anticough activity of Psidium guajava Linn. (guava) leaf extract was evaluated in rats and guinea pigs. The results showed that water extract of the plant at doses of 2 and 5 g/kg, p.o. decreased the frequency of cough induced by capsaicin aerosol by 35 and 54%, respectively, as compared to the control, within 10 min after injection of the extract, (P < 0.01). However, the anticough activity is less potent than that of 3 mg/kg dextromethorphan which decreased frequency of cough by 78% (P < 0.01). An experiment on isolated rat tracheal muscle showed that the extract directly stimulated muscle contraction and also synergized with the stimulatory effect of pilocarpine. This effect was antagonized by an atropine. Moreover, growth of Staphylococcus aureus and beta-streptococcus group A, as determined by the disc diffusion method, was inhibited by water, methanol and chloroform extract of dry guava leaves (P < 0.001). The LD50 of guava leaf extract was more than 5 g/kg, p.o. These results suggest that guava leaf extract is recommended as a cough remedy.  相似文献
3.
Inhibition of Naja kaouthia venom activities by plant polyphenols   总被引:4,自引:0,他引:4  
Plant polyphenols from the aqueous extracts of Pentace burmanica, Pithecellobium dulce, Areca catechu and Quercus infectoria were tested for their inhibitory activities against Naja kaouthia (NK) venom by in vitro neutralization method. The first three extracts could completely inhibit the lethality of the venom at 4 LD50 concentration and the venom necrotizing activity at the minimum necrotizing dose while also inhibited up to 90% of the acetylcholinesterase activity of NK venom at much lower tannin concentrations than that of Quercus infectoria. The ED50 of plant tannins in inhibiting NK venom activities varied according to condensed tannins and their content in the extracts. Molecular docking of the complexes between alpha-cobratoxin and either hydrolysable or condensed tannins at their lowest energetic conformations were proposed. The anti-venom activities of these plant polyphenols by selectively blocking the nicotinic acetylcholine receptor and non-selectively by precipitation of the venom proteins were suggested.  相似文献
4.
This study was designed to determine the antiproliferative, apoptotic and antioxidative properties of crude methanolic extract (CME) from the pericarp of Garcinia mangostana (family Guttiferae) using human breast cancer (SKBR3) cell line as a model system. SKBR3 cells were cultured in the presence of CME at various concentrations (0-50 microg/ml) for 48 h and the percentage of cell viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-di phenyl tetrazolium bromide (MTT) assay. CME showed a dose-dependent inhibition of cell proliferation with ED(50) of 9.25+/-0.64 microg/ml. We found that antiproliferative effect of CME was associated with apoptosis on breast cancer cell line by determinations of morphological changes and oligonucleosomal DNA fragments. In addition, CME at various concentrations and incubation times were also found to inhibit ROS production. These investigations suggested that the methanolic extract from the pericarp of Garcinia mangostana had strong antiproliferation, potent antioxidation and induction of apoptosis. Thus, it indicates that this substance can show different activities and has potential for cancer chemoprevention which were dose dependent as well as exposure time dependent.  相似文献
5.
Xanthones from the green fruit hulls of Garcinia mangostana   总被引:4,自引:0,他引:4  
Three new xanthones, mangostenol (1), mangostenone A (2), and mangostenone B (3), were isolated from the green fruit hulls of Garcinia mangostana, along with the known xanthones, trapezifolixanthone, tovophyllin B (4), alpha- and beta-mangostins, garcinone B, mangostinone, mangostanol, and the flavonoid epicatechin. The structures of the new xanthones were elucidated by analysis of their spectroscopic data.  相似文献
6.
The objective of this study was to investigate the inhibitory effect of the crude extracts from some herbs on adherence of Streptococcus mutans (S. mutans) ATCC 25175 and TPF-1 in vitro. Six herbs, Andrographis paniculata; Cassia alata; Chinese black tea (Camellia sinensis); guava (Psidium guajava); Harrisonia perforata and Streblus asper, were extracted with 50 or 95% ethanol and dried. Herbal extracted solution at 0.5% concentration (w/v) was initially tested for bacterial adherence on glass surfaces. In order to identify type and effective concentration of the extracts, the extracts that showed the inhibition on glass surfaces were then tested on saliva-coated hydroxyapatite by the use of radiolabeled bacteria. To study the mechanism of action, the effect of the extracts at such concentration on glucosyltransferase and glucan-binding lectin activities were examined. It was found that all extracts, but Streblus asper, showed significant inhibitory effect on bacterial adherence to glass surfaces. For the saliva-coated hydroxyapatite adherence assay, Andrographis paniculata, Cassia alata, Chinese black tea and Harrisonia perforata could inhibit adherence of S. mutans ATCC 25175. Chinese black tea was the strongest inhibitor followed by Andrographis paniculata, Cassia alata and Harrisonia perforata, respectively. For S. mutans TPF-1, adherence inhibition was observed from Andrographis paniculata and Cassia alata at similar levels. The lowest concentrations of the extracts that inhibited the adherence at least 50% were 0.5% of Andrographis paniculata, 0.5% of Cassia alata, 0.3% of Chinese black tea and 0.5% of Harrisonia perforata for S. mutans ATCC 25175. For S. mutans TPF-1, the effective concentrations were 0.5% of Andrographis paniculata and 0.4% of Cassia alata. All extracts at such concentrations decreased the activity of glucosyltransferase from both strains. Only Andrographis paniculata and Cassia alata eliminated or decreased the activity of glucan-binding lectin from both strains. These findings suggested that Andrographis paniculata, Cassia alata, Chinese black tea and Harrisonia perforata could inhibit adherence of S. mutans ATCC 25175, while Andrographis paniculata and Cassia alata had an effect on S. mutans TPF-1 in vitro at the concentrations employed in this study.  相似文献
7.
Modulatory influence of Andrographis paniculata crude extract on cytochrome P450 (CYP) enzymes was performed by administration of the crude extract of Andrographis paniculata to ICR male mice. Total hepatic P450 content was not significantly modified by either the aqueous or the alcoholic extracts of Andrographis paniculata. Assessment of hepatic microsomal P450 activities by alkoxyresorufin O-dealkylations noted that both the aqueous and alcoholic extracts of Andrographis paniculata significantly increased ethoxyresorufin O-dealkylase and pentoxyresorufin O-dealkylase activities, while those of methoxyresorufin O-dealkylase activities were not elevated. These results suggested that Andrographis paniculata might effectuate hepatic cytochrome P450 enzymes of which CYP1A1 and CYP2B are the responsive P450 isoforms.  相似文献
8.
Comparative repellency of 38 essential oils against mosquito bites   总被引:3,自引:0,他引:3  
The mosquito repellent activity of 38 essential oils from plants at three concentrations was screened against the mosquito Aedes aegypti under laboratory conditions using human subjects. On a volunteer's forearm, 0.1 mL of oil was applied per 30 cm2 of exposed skin. When the tested oils were applied at a 10% or 50% concentration, none of them prevented mosquito bites for as long as 2 h, but the undiluted oils of Cymbopogon nardus (citronella), Pogostemon cablin (patchuli), Syzygium aromaticum (clove) and Zanthoxylum limonella (Thai name: makaen) were the most effective and provided 2 h of complete repellency.From these initial results, three concentrations (10%, 50% and undiluted) of citronella, patchouli, clove and makaen were selected for repellency tests against Culex quinquefasciatus and Anopheles dirus. As expected, the undiluted oil showed the highest protection in each case. Clove oil gave the longest duration of 100% repellency (2-4 h) against all three species of mosquito.  相似文献
9.
Constituents of the leaves of Macaranga tanarius   总被引:3,自引:0,他引:3  
From the leaves of Macaranga tanarius, three new constituents, tanarifuranonol (1), tanariflavanone C (2), and tanariflavanone D (3), together with seven known compounds, were isolated and identified. Substances obtained in this investigation were evaluated against a panel of bioassays.  相似文献
10.
Neocrotocembranal from Croton oblongifolius.   总被引:2,自引:0,他引:2  
A new cembranoid diterpene, neocrotocembranal (3), was isolated from the stem bark of Croton oblongifolius. Its structure was established on the basis of spectroscopic analysis. This compound inhibited platelet aggregation induced by thrombin, with an IC50 value of 47.21 microg/mL, and exhibited cytotoxicity against P-388 cells in vitro, with an IC(50) value of 6.48 microg/mL.  相似文献
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