首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   215篇
  免费   1篇
  216篇
  2019年   1篇
  2017年   4篇
  2016年   4篇
  2015年   2篇
  2014年   6篇
  2013年   8篇
  2012年   5篇
  2011年   7篇
  2010年   10篇
  2009年   7篇
  2008年   13篇
  2007年   9篇
  2006年   12篇
  2005年   9篇
  2004年   6篇
  2003年   3篇
  2002年   7篇
  2001年   6篇
  2000年   9篇
  1999年   5篇
  1998年   3篇
  1995年   1篇
  1992年   4篇
  1991年   1篇
  1990年   8篇
  1989年   9篇
  1988年   9篇
  1987年   5篇
  1986年   2篇
  1985年   5篇
  1984年   5篇
  1983年   5篇
  1982年   4篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1978年   3篇
  1977年   4篇
  1976年   2篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
  1969年   1篇
  1968年   2篇
  1967年   1篇
  1966年   1篇
排序方式: 共有216条查询结果,搜索用时 15 毫秒
1.
Russian Journal of Bioorganic Chemistry - The anthocyanin composition of five purple leaves cultivars of Ocimum basilicum L. was investigated by reversed-phase HPLC with mass-spectrometric...  相似文献   
2.
3.
Earlier, we described a new family of mesophilic, strictly autotrophic Fe(2+)-oxidizing archaebacteria, Ferroplasmaceae, which belongs to the order Thermoplasmales and includes the genus Ferroplasma and species F. acidiphilum (strain YT) [1]. The present work is concerned with a comparative study of phenotypic characteristics of the type strain YT and a new strain, F. acidiphilum Y-2, isolated from dense pulps produced during oxidation of arsenogold concentrates from the Bakyrchikskoe (Kazakhstan) and Olimpiadinskoe (Krasnoyarsk Krai) ore deposits, respectively. The G + C content of DNA from strains YT and Y-2 comprised 35.1 and 35.2 mol%, respectively; the level of DNA-DNA homology between the strains was 84%. Restriction profiles of chromosomal DNA from both strains exhibited a similarity coefficient of 0.87. Genotypic characteristics of these strains indicate their affiliation to the same species. The cells of both strains are polymorphic and lack cell walls. Strains of F. acidiphilum oxidized ferrous oxide and pyrite as the sole source of energy and fixed carbon dioxide as the sole carbon source. Strains required yeast extract as a growth factor. Optimum pH for cell growth ranged from 1.7 to 1.8; the temperature optima for the growth of strains YT and Y-2 were 34-36 and 40-42 degrees C, respectively. Comparative analysis of total lipids revealed their close similarity in the strains; two glycophospholipids comprised 90% of total lipids: lipid I, beta-D-glucopyranosylcaldarchaetidylglycerol (about 55%), and lipid II, trihexosylcaldarchaetidylglycerol (26%), whose isopranyl chains contained no cyclopentane rings. The carbohydrate fraction of lipid I hydrolysate contained only D-glucose, whereas hydrolysate of lipid II contained both D-glucose and D-galactose in a molar ratio of 2:1. Thus, it was established that the intraspecific phylogenetic divergence within F. acidiphilum is manifested in two the strains by different temperature optima against the background of similarity in other phenotypic properties.  相似文献   
4.
    
We optimized the medium for cultivation of Penicillium roquefortii f39, a producer of roquefortine. In this medium, the roquefortine yield increased 1.5-2-fold. The increase in roquefortine content was associated with high biomass yield, but not with an increase in biosynthetic activity of the mycelium. Direct correlation was found between extracellular roquefortine concentration and amount of the inoculum. The introduction of sucrose into the growth medium allowed us to increase the concentration of roquefortine during fermentation to 90 mg/l.  相似文献   
5.
The potential of the polymerase chain reaction for the detection of ergot alkaloid producers among microscopic fungi of the genera Penicillium and Claviceps was evaluated. Twenty-three strains of various species of fungi with a previously studied capacity for alkaloid production were used. The internal fragment of the gene encoding 4-dimethylallyltryptophan synthase, the enzyme catalyzing the first step in the biosynthesis of ergot alkaloids, was amplified using degenerated primers. This approach revealed an about 1.2-kb specific DNA fragment in micromycetes synthesizing ergot alkaloids with complete tetracyclic ergoline system. Microorganisms that produce alkaloids with modified C or D ergoline rings, as well as alpha-cyclopiazonic acid, did not yield the PCR fragment of the expected size. This fragment was also not found in fungi incapable of ergot alkaloid production.  相似文献   
6.
The paper deals with the study of the ice nucleation activity of the cells, extracellular lipopolysaccharides (ELPSs), lipopolysaccharides (LPSs), and their structural components (lipid A, core oligosaccharide, and O-specific polysaccharide) of Pseudomonas fluorescens, P. syringae, P.fragi, and P. pseudoalcaligenes. The aqueous suspensions of the intact cells of P. syringae IMV 1951 and IMV 185 began to freeze at -1 and -4 degrees C, respectively. This suggests that these cells possess ice nucleation activity. The aqueous cell suspensions of two other strains, P. fluorescens IMV 1433 and IMV 2125, began to freeze at lower temperatures than did distilled water (-9 degrees C), which suggests that the cells of these strains possess antifreeze activity. The ice nucleation activity of the bacterial strains studied did not show any correlation with their taxonomic status. The ice nucleation activity of ELPSs depended little on their concentration (within a concentration range of 0.2-0.4%). In most cases, the ice nucleation activity of ELPSs, LPSs, and their structural components differed from that of the intact cells from which these biopolymers were obtained. This may indicate that the biopolymers under study play a role in ice nucleation, but this role is not crucial. The relationship between the structure of LPSs and their effect on ice nucleation is discussed.  相似文献   
7.
8.
The cyclic permutation and terminal redundancy were found in the genomes of Erwinia carotovora temperate bacteriophage 59 by electron microscopic studies. The headful mechanism for bacteriophage DNA cleavage and packaging during the phage morphogenesis was confirmed by the restriction analysis technique. Restriction map of the bacteriophage 59 DNA was constructed for restriction endonucleases BamHI, Bg1II, Eco31, Sa1I, SmaI, EcoRI.  相似文献   
9.
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号