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51.
Production of biosurfactants by acidophilic mycobacteria was demonstrated in the course of aerobic degradation of hydrocarbons (n-tridecane, n-tricosane, n-hexacosane, model mixtures of С14–С17, С12?С19, and С9–С21n-alkanes, 2,2,4,4,6,8,8-heptamethylnonane, squalane, and butylcyclohexane) and their complex mixtures (hydrocarbon gas condensate, kerosene, black oil, and paraffin oil) under extremely acidic conditions (pH 2.5). When grown on hydrocarbons, the studied bacterial culture AGS10 caused a decrease in the surface and interfacial tension of the solutions (to the lowest observed values of 26.0 and 1.3 mN/m, respectively) compared to the bacteria-free control. The rheological characteristics of the culture changed only when mycobacteria were grown on hydrocarbons. Neither the medium nor the cell-free culture liquid had the surfactant activity, which indicated formation of an endotype biosurfactant by mycobacteria. Biodegradation of n-alkanes was accompanied by an increase in cell numbers, surfactant production, and changes in the hydrophobicity of bacterial cell surface and in associated phenomena of adsorption and desorption to the hydrocarbon phase. Research on AGS10 culture liquids containing the raw biosurfactant demonstrated the preservation of its activity within a broad range of pH, temperature, and salinity. 相似文献
52.
M. G. Smaragdov E. I. Saksa A. A. Kudinov N. V. Dement’eva O. V. Mitrofanova K. V. Plemyashov 《Russian Journal of Genetics》2016,52(2):173-179
To form a reference population necessary for genomic selection of dairy cattle, it is important to acquire information on the genetic diversity of the base population. Our report is the first among the studies on breeding of farm animals to implement Wright’s F-statistics for this purpose. Genotyping of animals was performed using BovineSNP50 chip. In total, we genotyped 499 heifers from 13 breeding farms in the Leningrad region. We calculated Weir and Cockerham’s Fst estimate for all pairwise combinations of herds from breeding farms and the values obtained were in the range of 0.016–0.115 with the mean of 0.076 ± 0.002. Theoretical Fst values for the same pairwise combinations of herds were calculated using the ADMIXTURE program. These values were significantly (P < 0.05) higher than Weir and Cockerham’s Fst estimates and fell in the range of 0.063–0.136 with the mean of 0.100 ± 0.001. We discuss the reasons for this discrepancy between the two sets of Fst data. The obtained Fst values were used to identify reliable molecular-genetical differences between the herds. The ADMIXTURE program breaks the pool of 476 heifers into 16 subpopulations, the number of which is close to the number of herds used in the experiment. Results of the comparison between Fst values obtained using SNP markers with published data obtained on microsatellites are in support of the common opinion that microsatellite analysis results in underestimation of Fst values. On the whole, the obtained across-herd Fst values are in the range Fst data reported for cattle breeds. Results of comparison of Fst values with the data on the origin of bulls imported from different countries lead to the conclusion on the expediency of the use of Fst data to assess heterogeneity of the herds. Thus, we have demonstrated that use of Fst data provides the means to assess genetic diversity of cattle herds and is a necessary step in the formation of a reference population for dairy cattle. 相似文献
53.
N. Yu. Kim O. D. Novikova V. A. Khomenko G. N. Likhatskaya O. P. Vostrikova V. I. Emel’yanenko S. M. Kuznetsova T. F. Solov’eva 《Biochemistry (Moscow) Supplemental Series A: Membrane and Cell Biology》2007,1(2):145-153
The changes in the structural and functional properties of yersinin, a porin from the outer membrane of Yersinia pseudotuberculosis, were studied in the pH range 8.0–2.0 using SDs-PAGE, scanning microcalorimetry, optical spectroscopy and bilayer lipid membrane technique. It was found that in the pH range under study the changes in the spatial structure of yersinin were biphasic. In the first steps of pH titration (pH 8.0–4.5), porin underwent a series of conformational transitions, which did not affect the trimeric structure of its molecule. In the second step (pH 4.0–2.0), structural rearrangements led to dissociation of the protein trimers into monomers. It is noteworthy that complete unfolding of the polypeptide chain of the protein was not observed even at low values of pH. Thus, at pH 2.0 the conformational intermediate of the protein retained up to 50% of its regular secondary structure. Studies of current fluctuations in the bilayer lipid membrane revealed that in weakly acidic media the conductivity of yersinin pores was decreased by one order of magnitude. The most drastic changes in the conductivity of the model membrane were observed at pH 5.8, whereas a further decrease of pH to 5.0 resulted in the closure of porin channels. It was concluded that the observed changes in the pore-forming properties of yersinin in a narrow range of pH represent an early step in the adaptation of bacteria to the changing conditions of the environment and entail control over the biosynthesis of nonspecific porins. The pH-dependent changes in the structure and pore-forming properties of yersinin provide additional evidence in favor of conformational and functional plasticity of porins. 相似文献
54.
55.
56.
O. D. Novikova V. A. Khomenko V. I. Emelyanenko G. N. Likhatskaya E. A. Zelepuga N. Yu. Kim M. P. Isaeva O. Yu. Portnyagina O. P. Vostrikova O. V. Sidorova T. F. Solov’eva 《Biochemistry (Moscow) Supplemental Series A: Membrane and Cell Biology》2011,5(3):263-277
Pore-forming protein from the outer membrane of Yersinia pseudotuberculosis cultured at 37°C has been isolated and characterized. Comparative analysis of the primary and three-dimensional structures of this protein and of OmpC porin from E. coli was carried out, functional properties of these proteins have been studied using bilayer lipid membranes (BLM) technique. The degree of homology, molecular mass and pore-forming properties of the isolated porin was found to be closer to those of OmpC porin from E. coli than OmpF porin from Y. pseudotuberculosis. The value of the most probable conductivity of OmpC porin from Y. pseudotuberculosis (0.18 pS) in BLM corresponded to the conductivity of the native trimer of this protein. Using CD spectroscopy, the porins investigated were shown to belong to the β-structured proteins. Data of the primary structure and intrinsic protein fluorescence revealed essential differences in localization and microenvironment of tryptophan residues in the porins investigated. Participation of external loops L2 and L6 in the formation of the antigenic structure of OmpC porin from Y. pseudotuberculosis was demonstrated. On the basis of crystal structure of osmoporin from Klebsiella pneumoniae, three-dimensional models of the monomer and trimer of the Y. pseudotuberculosis porin were obtained. Using Web server AGGRESCAN, the localization of protein structure sites with the increased aggregation capability (hot spots) has been deter-mined. It turned out that some of these zones localize in the region of intramonomeric contacts in the porin trimer; however, a large part of them is located on the external surface of the β-barrel. The process of thermal denaturation has been studied and the melting points of the porins were determined. It was found that significant changes in the microenvironment of the indole fluorophores (especially tryptophan residues of spectral class I) took place in the process of the thermodenaturation of the proteins. These changes preceded the irreversible conformational transition observed for the E. coli porin at 77°C and for the Y. pseudotuberculosis porin at 70°C. 相似文献
57.
Yu. A. Bukurova S. L. Khankin G. S. Krasnov E. S. Grigor’eva T. D. Mashkova N. A. Lisitsyn V. L. Karpov S. F. Beresten’ 《Molecular Biology》2010,44(2):334-340
A modification of proteome differential analysis was developed; it comprises initial removal of the cell structural proteins by extraction with buffered saline and protein fractionation by gel filtration with subsequent separation by two-dimensional gel electrophoresis and identification by mass-spectrometry. This approach provided for detection of 12 proteins with significantly elevated expression levels in the majority of the analyzed malignant colorectal tumor specimens as compared with normal tissues. Increased contents of eight proteins were discovered for the first time. The efficiencies of the search for tumor markers by 2D analysis and serial analysis of gene expression (SAGE) were compared using the control panel of 19 potential colorectal tumor markers, identified earlier or independently found by other researchers. The 2D data for the control panel matched the earlier published data, whereas the search of SAGE database succeeded in detection only one-third of the markers. 相似文献
58.
The plant hormone auxin plays a major role in a variety of growth and developmental responses, even in the more ancient plants-for example, cell differentiation in mosses. Nevertheless, almost nothing is known about the distribution of auxin during moss development. To address this question, we characterised auxin distribution in the moss Physcomitrella patens using auxin-inducible reporter gene systems. Stable transgenic Physcomitrella plants were produced expressing the beta-glucuronidase (GUS) gene driven by the auxin-inducible promoters GH3 and DR5, respectively. Both fusions showed remarkable differences with respect to auxin-induced promoter strength and expression kinetics. A detailed characterisation of the GUS expression pattern in different developmental stages revealed that the highest auxin concentrations were in dividing and ontogenetic young cells. 相似文献
59.
E.?V.?Vorob’evaEmail author A.?S.?Dmitrenok P.?S.?Dmitrenok V.?V.?Isakov I.?N.?Krasikova T.?F.?Solov’eva 《Russian Journal of Bioorganic Chemistry》2005,31(4):362-371
Lipid A was obtained in a high yield (27%) by the hydrolysis of lipopolysaccharide from the marine gamma proteobacterium Marinomonas communis ATCC 27118T with 1% AcOH. Using chemical analysis and 1D and 2D NMR spectroscopic and fast atom bombardment mass spectrometric methods, it was shown to be β-1′,6-linked D-glucosaminobiose 1-phosphate acylated with (R)-3-dodecanoyl- or (R)-3-decanoyloxydecanoic acid, (R)-3-{(R)-3-hydroxydecanoyloxy)]decanoic acid and (R)-3-hydroxydecanoic acid at the C2, C2′ and C3 positions, respectively. Uncommon structural peculiarities (a low acylation and phosphorylation degree) of the M .communis lipid A in comparison with those of terrestrial bacteria may be of pharmacological interest. The potential physiological meaning of this lipid A and compounds of similar structure are discussed.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 4, 2005, pp. 404–413.Original Russian Text Copyright © 2005 by Vorob’eva, A. Dmitrenok, P. Dmitrenok, Isakov, Krasikova, Solov’eva.The article was translated by the authors. 相似文献
60.
Tina Kamčeva Maja Radisavljević Iva Vukićević Jürgen Arnhold Marijana Petković 《化学与生物多样性》2013,10(11):1972-1986
Phospholipase A2 is involved in propagation of inflammatory processes and carcinogenesis through its role in phospholipid metabolism, and release of arachidonic acid and lysophospholipids. Recent findings on correlation between elevated PLA2 activity and metastatic cancer render this enzyme an attractive target for cancer therapy. On the other hand, due to a broad range of oxidation states under physiological conditions and a high affinity for protein binding, platinum and ruthenium coordination complexes are promising candidates for PLA2 inhibitors. In this article, we discuss the interactions of Pt and Ru coordination complexes with PLA2 and phospholipids, as well as the application of MALDI‐TOF mass spectrometry for screening PLA2 inhibitors. Owing to the ability of this technique to simultaneously detect and monitor changes in substrate and product concentrations, the inhibitor mechanisms of both Pt and Ru complexes with various ligands were determined. 相似文献