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排序方式: 共有96条查询结果,搜索用时 17 毫秒
1.
E. N. Olsuf’eva S. E. Solov’eva M. I. Reznikova A. M. Korolev M. N. Preobrazhenskaya 《Russian Journal of Bioorganic Chemistry》2013,39(2):121-130
The coupling reagent (benzotriazole-1-yl)oxy-tris(pyrrolidino)phosphonium hexafluorophosphate (PyBOP) is widely used for the synthesis of different peptides and their amides, particularly carboxamides of glycopeptide antibiotics of the vancomycin or teicoplanin groups. The amidation reaction of the carboxyl group of the seventh amino acid residue (AA7) in antibiotics in the presence of PyBOP is not usually accompanied by the formation of significant amounts of byproducts. However, the amidation of eremomycin (I) with bulky amines (e.g., decyl amine and adamantyl amine) in the presence of PyBOP at pH ~8.5 (Et3N or (i-Pr)2EtN) yielded N-unsubstituted carboxamide of eremomycin (Ia) as an admixture. The interaction of asparagine-containing antibiotics (eremomycin or vancomycin) with the excess of PyBOP and Et3N (pH ~8.5) in the absence of amine or ammonia led to the formation of still larger amounts of corresponding unsubstituted AA7-amides (~20%). Their structure was determined by 1H NMR and ESI MS methods and confirmed by comparing with authentic samples. It is assumed that the amide group of the asparagine residue (AA3) is the source of ammonia in the unususal amidation reaction of Asn-containing antibiotics. 相似文献
2.
E.?S.?StarodubovaEmail author Y.?V.?Kuzmenko A.?A.?Latanova O.?V.?Preobrazhenskaya V.?L.?Karpov 《Molecular Biology》2017,51(3):404-407
The glycoprotein of rabies virus is the central antigen elicited the immune response to infection; therefore, the majority of developing anti-rabies vaccines are based on this protein. In order to increase the efficacy of DNA immunogen encoding rabies virus glycoprotein, the construction of chimeric protein with the CD63 domain has been proposed. The CD63 is a transmembrane protein localized on the cell surface and in lysosomes. The lysosome targeting motif GYEVM is located at its C-terminus. We used the domain that bears this motif (c-CD63) to generate chimeric glycoprotein in order to relocalize it into lysosomes. Here, it was shown that, in cells transfected with plasmid that encodes glycoprotein with c-CD63 motif at the C-terminus, the chimeric protein was predominantly observed in lysosomes and at the cell membrane where the unmodified glycoprotein is localized in the endoplasmic reticulum and at the cell surface. We suppose that current modification of the glycoprotein may improve the immunogenicity of anti-rabies DNA vaccines due to more efficient antibody production. 相似文献
3.
Shchekotikhin AE Glazunova VA Luzikov YN Buyanov VN Susova OY Shtil AA Preobrazhenskaya MN 《Bioorganic & medicinal chemistry》2006,14(15):5241-5251
We describe the synthesis of derivatives of 4,11-diaminonaphtho[2,3-f]indole-5,10-dione and their cytotoxicity for human tumor cells that express major determinants of altered anticancer drug response, the efflux pump P-glycoprotein, and non-functional p53. Nucleophilic substitution of methoxy groups in 4,11-dimethoxynaphtho[2,3-f]indole-5,10-dione with various ethylenediamines yielded the derivatives of 4,11-diaminonaphtho[2,3-f]indole-5,10-dione, the indole containing analogues of the antitumor agent ametantrone. The cytotoxicity of novel compounds for multidrug resistant, P-glycoprotein-expressing tumor cells is highly dependent on the N-substituent at the terminal amino group of the ethylenediamine moiety. Whereas p53 null colon carcinoma cells were less sensitive to the reference drug doxorubicin than their counterparts with wild type p53, the majority of novel naphthoindole derivatives were equally potent for both cell lines, regardless of the p53 status. 相似文献
4.
Lavrenov SN Korolev AM Reznikova MI Sosnov AV Preobrazhenskaya MN 《Carbohydrate research》2003,338(2):143-152
Alkaline degradation of the ascorbigen 2-C-[(indol-3-yl)methyl]-alpha-L-xylo-hex-3-ulofuranosono-1,4-lactone (1a) led to a mixture of 1-deoxy-1-(indol-3-yl)-L-sorbose (2a) and 1-deoxy-1-(indol-3-yl)-L-tagatose (3a). The mixture of diastereomeric ketoses underwent acetylation and pyranose ring opening under the action of acetic anhydride in pyridine in the presence of 4-dimethylaminopyridine (DMAP) with the formation of a mixture of (E)-2,3,4,5,6-penta-O-acetyl-1-deoxy-1-(indol-3-yl)-L-xylo-hex-1-enitol (4a) and (E)-2,3,4,5,6-penta-O-acetyl-1-deoxy-1-(indol-3-yl)-L-lyxo-hex-1-enitol (5a), which were separated chromatographically. Deacetylation of 4a or 5a afforded cyclised tetrols, tosylation of which in admixture resulted in 1-deoxy-1-(indol-3-yl)-3,5-di-O-tosyl-alpha-L-sorbopyranose (12a) and 1-deoxy-1-(indol-3-yl)-4,5-di-O-tosyl-alpha-L-tagatopyranose (13a). Under alkaline conditions 13a readily formed 2-hydroxy-4-hydroxymethyl-3-(indol-3-yl)cyclopenten-2-one (15a) in 90% yield. Similar transformations were performed for N-methyl- and N-methoxyindole derivatives. 相似文献
5.
The tropane alkaloid (TA) scopolamine is suggested to protect Brugmansia suaveolens (Solanaceae) against herbivorous insects. To test this prediction in a natural environment, scopolamine was induced by methyl jasmonate (MJ) in potted plants which were left 10?days in the field. MJ-treated plants increased their scopolamine concentration in leaves and herbivory decreased. These findings suggest a cause?Ceffect relationship. However, experiments in laboratory showed that scopolamine affect differently the performance of the specialist larvae of the ithomiine butterfly Placidina euryanassa (C. Felder & R. Felder) and the generalist fall armyworm Spodoptera frugiperda (J. E. Smith): the specialist that sequester this TA from B. suaveolens leaves was not negatively affected, but the generalist was. Therefore, scopolamine probably acts only against insects that are not adapted to TAs. Other compounds that are MJ elicited may also play a role in plant resistance against herbivory by generalist and specialist insects, and deserve future investigations. 相似文献
6.
Anticoagulant activity of fucoidans from brown algae 总被引:1,自引:0,他引:1
N. A. Ushakova G. E. Morozevich N. E. Ustyuzhanina M. I. Bilan A. I. Usov N. E. Nifantiev M. E. Preobrazhenskaya 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2009,3(1):77-83
The anticoagulant activity of polysaccharide fucoidans from 11 species of brown algae was studied. The anticoagulant activity was measured by the activated partial thromboplastin time (APTT), prothrombin time, and thrombin time. Inhibitory action of these fucoidans significantly varied from one species to another. Fucoidans from Laminaria saccharina and Fucus distichus exhibited high anticoagulant activity, while fucoidans from Cladosiphon okamuranus and Analipus japonicus were almost inactive. Other fucoidans exhibited intermediate inhibitory activity. The inhibitory effect of fucoidans on thrombin and factor Xa was investigated in the presence or in the absence of natural thrombin inhibitor, antithrombin III (AT III). In contrast to the best-studied anticoagulant, heparin, most of these fucoidans inhibited thrombin in the absence of AT III. In the presence of AT III the inhibitory effect of fucoidans considerably increased. In contrast to heparin, fucoidans weakly influenced factor Xa activity in the presence of AT III and their inhibitory effect was not observed in the absence of AT III. There was no correlation between the anticoagulant activities of this series of fucoidans and their anti-inflammatory action, studied earlier. It is suggested that these two types of fucoidan activities depend on different structural features of fucoidans. Results of this study demonstrate a possibility of preparation of fucoidans with high anti-inflammatory activity but low anticoagulant activity. Anticoagulant activity of the fucoidans did not exhibit direct dependence on the content of fucose, the other neutral sugars and sulfates; no dependence was also found between the anticoagulant activity and the structure of the backbone of their molecules. 相似文献
7.
O. N. Pavlyuk T. V. Preobrazhenskaya T. S. Tarasova 《Russian Journal of Marine Biology》2001,27(2):105-110
We performed a comparative analysis of the taxonomical composition and population density of the meiobenthos and substrate types of Alekseev Bight, Sea of Japan, throughout the period when a plantation for mariculture of Japanese scallop was exploited in the bight and for a decade after the plantation had been removed. We found that silting of substrates in the bight decreased and the number of taxonomical groups that constituted the meiobenthos increased. The nematodes that, earlier, dominated the meiobenthos in terms of population density were later exceeded by foraminiferans, the species diversity of which increased. Changes are revealed in the composition of the dominant species of these groups. 相似文献
8.
Yu. V. Preobrazhenskaya Yu. A. Bogdevich V. N. Burd’ 《Applied Biochemistry and Microbiology》2006,42(2):134-137
A method for the immobilization of chloroperoxidase from the bacterial strain Serratia marcescens in semi-permeable membranes was developed based on the following proteins: bovine serum albumin, gelatin, ribonuclease, cytochrom
C, and the protein of the covering layer of Bacillus sphaericus cells. Estimation of the activity and stability of immobilized preparations in a batch reactor was carried out.
Published in Russian in Prikladnaya Biokhimiya i Mikrobiologiya, 2006, Vol. 42, No. 2, pp. 152–155.
This article was translated by the authors. 相似文献
9.
MN Kaggwa N Straubinger-Gansberger M Schagerl 《African Journal of Aquatic Science》2018,43(2):123-129
Nine small artificial dams located in different climatic regions of Kenya were studied. The local communities use the stored water for various purposes, such as irrigation, domestic use, watering of livestock and cage fish farming. Such intense use is commonly accompanied by eutrophication, including fast growth of cyanobacteria, which at times produce cyanotoxins threatening human and animal life. We studied the pelagic community, analysed abiotic variables and identified microcystins by means of high performance liquid chromatography and ELISA kits at monthly intervals over a period of one year. Mass spectrometry (MALDI-TOF MS) was used to identify structural variants of microcystins by their protonated masses (M + H). Three dams contained microcystins, with the highly toxic Microcystin-LR being identified as the most prominent substance. Cell content of the toxin varied from 7.2 to 686.7 fg cell?1. Basic limnological variables that indicate the probability of toxin presence were also recorded. Non-parametric Mann–Whitney U-test revealed significant differences in soluble reactive phosphorous, nitrate-N, water depth, total hardness and post-Nauplii stages sampled between toxin-producing and non-toxin-producing dams. Although most of the samples did not contain high amounts of cyanobacteria, the cyanotoxin-problem was evident, suggesting the need for regular cyanotoxin monitoring programs. 相似文献
10.
L. G. Dezhenkova A. N. Tevyashova E. N. Olsuf’eva I. D. Treshchalin A. A. Shtil M. N. Preobrazhenskaya 《Russian Journal of Bioorganic Chemistry》2008,34(3):387-389
The relationship between the structure of new semisynthetic derivatives of doxorubicin, daunorubicin, and carminomycin and their ability to inhibit topoisomerase I were studied. The new derivatives inhibit the activity of topoisomerase I at low concentrations, induce the death of K-562 leukemia cells in culture, and produce an antitumor effect in experimental animals bearing P388 leukemia. 相似文献