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71.
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73.
Dini C Collette P Drochon N Guillot JC Lemoine G Mauvais P Aszodi J 《Bioorganic & medicinal chemistry letters》2000,10(16):1839-1843
Tunicamycins (TCMs) and liposidomycins (LPMs) are naturally occurring inhibitors of the bacterial translocase (MraY). Based on structure-activity relationship (SAR) studies, a molecular model has been proposed for their inhibitory mechanism. This study points out the importance of the nucleoside moiety of liposidomycins in the inhibition of MraY. A simplified molecule (I) based on the liposidomycin core structure has been synthesised and tested on MraY. The compound displayed a moderate inhibitory activity (IC50 = 50 microM). The validation of the molecular model was then performed by synthesising higher homologues of I, containing an additional stereocentre in the 5' position (XIV and XV). In agreement with the prediction, only the (S) isomer XV showed significant activity against MraY (IC50 = 5 microM). 相似文献
74.
As part of an effort to discover novel antibacterial agents, a new and efficient synthesis was established in order to provide a large amount of UDP-N-acetylmuramic acid (UDP-MurNAc). 相似文献
75.
Dini C Didier-Laurent S Drochon N Feteanu S Guillot JC Monti F Uridat E Zhang J Aszodi J 《Bioorganic & medicinal chemistry letters》2002,12(8):1209-1213
The synthesis and inhibitory activity against MraY of a series of simplified analogues of liposidomycins are described. These compounds were mainly obtained by performing parallel synthesis in the 6'-position of a scaffold that gathers key features found necessary for the binding to MraY. Thus, inhibitory activity was improved from 5300 to 140 nM. This improvement was correlated with the length and lipophilicity of substituents, but was found to be independent of the nature of the chemical bond generated. In addition, some of these inhibitors presented encouraging antibacterial activities. 相似文献
76.
H. Sathyapriya M. Sariah A. Siti Nor Akmar M. Wong 《The Annals of applied biology》2012,160(2):137-144
Pseudomonas aeruginosa strain UPMP3 labelled with β‐glucuronidase (gusA) and green fluorescent protein (gfp) by electrotransformation yielded ca 1 × 107 transformants µg?1 DNA. The data obtained from the dilution plate count showed that over 28 days both epiphytic and endophytic populations of P. aeruginosa strain UPMP3 increased from 5.76 log10 [colony forming unit (CFU) + 1] g?1 fresh weight (FW) to 8.19 log10 (CFU + 1) g?1 FW and 4.10 log10 (CFU + 1) g?1 FW to 6.23 (CFU + 1) g?1 FW, respectively. Confocal laser scanning microscopic analysis of oil palm roots treated with gusA:gfp‐tagged P. aeruginosa strain UPMP3 showed intense root colonisation over the sampling period. The root surface colonisation by P. aeruginosa strain UPMP3 was followed by a second stage, characterised by cortical infection, and a third stage, which involves xylem ingression. The colonisation of oil palm roots by the gusA:gfp‐tagged strain was concentrated on root areas potentially rich in nutrients such as the elongation zones, ridges between epidermal cells and points of secondary adventitious root emergence. Different expression levels of defence‐related genes, namely, chitinase and β‐1,3‐glucanase in the strain UPMP3–host interaction recorded over 28 days, suggested the potential role of P. aeruginosa strain UPMP3 in triggering the defence mechanism in oil palm. This is the first report on root colonisation and upregulation of defence‐related genes on oil palm roots by P. aeruginosa strain UPMP3 and shows the potential of this strain to be used as a biocontrol agent in oil palm. 相似文献
77.
FL Soares IS Melo AC Dias FD Andreote 《World journal of microbiology & biotechnology》2012,28(5):2195-2203
It is believed that the exposure of organisms to harsh climate conditions may select for differential enzymatic activities,
making the surviving organisms a very promising source for bioprospecting. Soil bacteria play an important role in degradation
of organic matter, which is mostly due to their ability to decompose cellulose-based materials. This work focuses on the isolation
and identification of cellulolytic bacteria from soil found in two environments with stressful climate conditions (Antarctica
and the Brazilian semi-arid caatinga). Cellulolytic bacteria were selected using enrichments at high and low temperatures
(4 or 60°C) in liquid media (trypic soy broth—TSB and minimum salt medium—MM) supplemented with cellulose (1%). Many of the
isolates (119 out of 254—46.9%) displayed the ability to degrade carboxymethyl-cellulose, indicating the presence of endoglucolytic
activity, while only a minority of these isolates (23 out of 254—9.1%) showed exoglucolytic activity (degradation of avicel).
The obtained isolates revealed a preferential endoglucolytic activity according to the temperature of enrichments. Also, the
identification of some isolates by partial sequencing of the 16S rRNA gene indicated that the Bacteroidetes (e.g., Pedobacter, Chryseobacterium and Flavobacterium) were the main phylum of cellulolytic bacteria isolated from soil in Antarctica; the Firmicutes (e.g., Bacillus) were more commonly isolated from samples from the caatinga; and Actinobacteria were found in both types of soil (e.g., Microbacterium and Arthrobacter). In conclusion, this work reports the isolation of bacteria able to degrade cellulose-based material from soil at very low
or very high temperatures, a finding that should be further explored in the search for cellulolytic enzymes to be used in
the bioenergy industry. 相似文献
78.
MA Nakisah MY Ida Muryany H Fatimah R Nor Fadilah MR Zalilawati S Khamsah M Habsah 《World journal of microbiology & biotechnology》2012,28(3):1237-1244
Crude methanol extracts of a marine sponge, Aaptos
aaptos, collected from three different localities namely Kapas, Perhentian and Redang Islands, Terengganu, Malaysia, were tested
in vitro on a pathogenic Acanthamoeba castellanii (IMR isolate) to examine their anti-amoebic potential. The examination of anti-Acanthamoebic activity of the extracts was
conducted in 24 well plates for 72 h at 30 °C. All extracts possessed anti-amoebic activity with their IC50 values ranging from 0.615 to 0.876 mg/mL. The effect of the methanol extracts on the surface morphology of A. castellanii was analysed under scanning electron microscopy. The ability of the extracts to disrupt the amoeba cell membrane was indicated
by extensive cell’s blebbing, changes in the surface morphology, reduced in cell size and with cystic appearance of extract-treated
Acanthamoeba. Number of acanthapodia and food cup was also reduced in this Acanthamoeba. Morphological criteria of apoptosis in Acanthamoeba following treatment with the sponge’s extracts was determined by acridine orange-propidium iodide staining and observed by
fluorescence microscopy. By this technique, apoptotic and necrotic cells can be visualized and quantified. The genotoxic potential
of the methanol extracts was performed by the alkaline comet assay. All methanol extracts used were significantly induced
DNA damage compared to untreated Acanthamoeba by having high percentage of scores 1, 2, and 3 of the DNA damage. Results from cytotoxicity and genotoxicity studies carried
out in the present study suggest that all methanol extracts of A. aaptos have anti-amoebic properties against A. castellanii. 相似文献
79.
Wei AC Ali MA Yoon YK Ismail R Choon TS Kumar RS Arumugam N Almansour AI Osman H 《Bioorganic & medicinal chemistry letters》2012,22(15):4930-4933
A series of twelve dispiropyrrolidines were synthesized using [3+2]-cycloaddition reactions. The synthesized compounds were screened for their antimycobacterial activity against M. tuberculosis H(37)Rv and INH resistant M. tuberculosis strains using agar dilution method, four of them showed good activity with MIC of less than 1 μM. Compound 4'-[5-(4-fluorophenyl)pyridin-3-yl]-1'-methyldispiro[indan-2,2' pyrrolidine-3',2″-indan]-1,3,1″-trione (4b) was found to be the most active with MIC of 0.1215 and 5.121 μM, respectively. 相似文献
80.
Ashraf Ali M Ismail R Choon TS Kumar RS Osman H Arumugam N Almansour AI Elumalai K Singh A 《Bioorganic & medicinal chemistry letters》2012,22(1):508-511
Pyrrolothiazolyloxindole analogues share vital pharmacological properties, considered useful in Alzheimer's disease (AD). The aim of this study was synthesis and evaluate pyralothiazolyloxindole analogues if possess acetyl cholinesterase (AChE) inhibitory activity. The easily accessible one-pot synthesis of these compounds resulted to be significantly less difficult and expensive than that of donepezil. Several compounds possess anti-cholinesterase activity in the order of micro and sub-micromolar. Particularly, compound was the most potent inhibitors of the series against acetyl cholinesterase enzyme with IC(50) 0.11μmol/L. 相似文献