全文获取类型
收费全文 | 274篇 |
免费 | 5篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 13篇 |
2017年 | 10篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 10篇 |
2011年 | 12篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 9篇 |
2002年 | 12篇 |
2001年 | 10篇 |
2000年 | 16篇 |
1999年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 12篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 5篇 |
1970年 | 1篇 |
1969年 | 4篇 |
1968年 | 5篇 |
1966年 | 2篇 |
排序方式: 共有279条查询结果,搜索用时 375 毫秒
51.
Aleksandrova M. A. Revishchin A. V. Poltavtseva R. A. Cherkasova L. V. Kleshchinov V. N. Korochkin L. I. Sukhikh G. T. 《Russian Journal of Developmental Biology》2003,34(3):131-136
We studied the development of stem/progenitor cells of the human brain transplanted in the adult rat brain after expansion in an in vitrotissue culture. It was preliminarily shown by the immunological methods that the stem cells grown in a medium with growth factors formed neurospheres, which were heterogenous and contained both stem and progenitor cells of the human brain. The cells were implanted in the hippocampus, striatum, or lateral ventricle of the rat brain as a suspension or aggregates (neurospheres) and their behavior and differentiation were studies within 10, 20, and 30 days using the morphological and immunochemical methods. The cultured cells of the human brain continued their development in the rat brain, migrated, and formed neurons and astrocytes. The white mater fibers, lateral ventricle wall, and perivascular spaces served as the main pathways of migration. The neuronal differentiation was shown by staining with antibodies to -tubulin III, neurofilaments-70, and calbindin. Some growing nerve cells had long processes with growth cones. At the same time, some transplanted cells retained the undifferentiated state within one month after the implantation, as shown by the vimentin expression. 相似文献
52.
Clemens Wittenbecher Romina di Giuseppe Ronald Biemann Juliane Menzel Maria Arregui Juliane Hoffmann Krasimira Aleksandrova Heiner Boeing Berend Isermann Matthias B. Schulze Cornelia Weikert 《PloS one》2015,10(9)
The reliability of single time point measurements of the novel adipokines retinol-binding protein 4 and omentin-1 in the blood has not been evaluated in large samples yet. The present study aimed to assess the amount of biological variation of these two adipokines within individuals. The study sample comprised 207 participants (124 women and 83 men) from Potsdam (Germany) and surrounding areas, with an average age of 56.5 years (SD 4.2). Blood samples were collected from each participant twice, approximately four months apart. Using enzyme linked immunosorbent assays, the concentrations of retinol-binding protein 4 and omentin-1 were determined in EDTA plasma. As indicators of reliability, intraclass correlation coefficients (ICCs) were calculated from the repeated biomarker measurements. The ICCs for repeated retinol-binding protein 4 and omentin-1 measurements were 0.77 (95% CI 0.71, 0.82) and 0.83 (95% CI 0.78, 0.87), respectively, indicating for both adipokines excellent reliability. ICCs were stable across strata according to sex, age, BMI, and blood pressure. Thus, for epidemiological studies it seems reasonable to rely on concentrations of retinol-binding protein 4 and omentin-1 in samples from a single time point if repeated measurements are not available. 相似文献
53.
S. S. Terekhov T. V. Bobik Yu. A. Mokrushina A. V. Stepanova N. M. Aleksandrova I. V. Smirnov A. A. Belogurov N. A. Ponomarenko A. G. Gabibov 《Applied Biochemistry and Microbiology》2016,52(2):162-169
A platform for the cloning and expression of active human butyrylcholinesterase (BuChE) in the yeast Pichia рastoris is first presented. Genetic constructs for BuChE gene expression, separately and in conjunction with a proline-rich peptide called proline-rich attachment domain (PRAD), are based on the vector pPICZαA. It is shown that the highest level of production is achieved in the expression of a BuChE gene without PRAD pPICZαA. It is found that one can obtain up to 125 mg of active enzyme from 1 L of culture medium at an optimal pH environment (pH 7.6), an optical seed culture density of 3 o.u., and an optimum methanol addition mode of (0.5% methanol in the first day and 0.2% thereafter from the second day). 相似文献
54.
55.
56.
57.
D. V. Grishin D. D. Zhdanov Ju. A. Gladilina V. S. Pokrovsky O. V. Podobed M. V. Pokrovskaya S. S. Aleksandrova A. L. Milyushkina M. A. Vigovskiy N. N. Sokolov 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2018,12(2):143-150
In this work, a recombinant chemotaxis CheW protein from Thermotoga petrophila RKU-1 (TpeCheW) and its mutant homologue (TpeCheW-mut) have been obtained. Despite the low homology with the CheW protein of the Escherichia coli bacteria, these proteins do not cause metabolic overload and are well expressed by E. coli laboratory strains. A wide range of features and parameters important for isolation of the TpeCheW-mut protein, such as stability over a wide range of temperatures and pH values, high level of expression, solubility, and the possibility of using simple low-stage purification schemes, including heat pretreatment, has been recognized. Possible directions of using this protein in the practice of scientific and applied research have been formulated and justified. 相似文献
58.
R. Daraktchiev V. Beschkov N. Kolev T. Aleksandrova 《Bioprocess and biosystems engineering》1997,16(2):115-117
The bioreactor with a semi-fixed packing consists of frames with stretched “Raschell”-type sacks on them. This construction enables the attainment of a larger interfacial area of the biofilm carrier per unit reactor volume as well as the easy removal of the exausted biomass at certain biofilm thickness. In the present paper the batch anaerobic conversion of lactose to lactic acid in this reactor with immobilized bacteria Lactobacillus casei is studied. The dilution rate of the feeding substrate solution was 1?mm/s. Comparison of our experimental results with data, obtained for free cells and other construction of bioreactors with immobilized cells is made. It is shown that the used immobilised biocatalyst is superior to free bacterial cells, or attached to the inner pores of polyurethane foam. 相似文献
59.
E L Riabkova G K Reshed'ko E D Agapova I A Aleksandrova N V Beloborodova T Iu Vostrikova D E Zdzitovetski? S F Ivanova V N Il'ina N E Marusina I G Multykh S V Polikarpova S V Skal'ski? T N Suborova I A Toropova V B Turkutiukov 《Antibiotiki i khimioterapii͡a》2005,50(8-9):43-51
Prevalence of Klebsiella pneumoniae among gramnegative pathogens of nosocomial infections in intensive care units of 33 hospitals of 22 towns in Russia was investigated. Antibiotic susceptibility and extended-spectrum beta-lactamase production were tested in 420 nosocomial K. pneumoniae isolates. Carbapenems (imipenem, meropenem and ertapenem) showed the highest activity. Extended-spectrum beta-lactamase production based on the phenotyping methods was revealed in 342 (81.4%) isolates. The maximum activity against the K. pneumoniae isolates producing extended-spectrum beta-lactamase was observed in imipenem and meropenem (no unsusceptible strains were isolated). 3.2% of the isolates was not susceptible to ertapenem. Differences in the activity of cefoperazone/sulbactam, amikacin, ciprofloxacin and levofloxacin against the extended-spectrum beta-lactamase producing isolates in various hospitals were recorded. 相似文献
60.
L A Aleksandrova A M Atrazhev M K Kukhanova A A Kraevski? 《Bioorganicheskaia khimiia》1987,13(5):643-647
A 2'-deoxyuridine 5'-triphosphate analogue with a dansyl (5-dimethylaminonaphtalene 1-sulphonyl) residue in the 5-position of uracyl has been synthesised. This compound substitutes dTTP in the DNA synthesis catalyzed by Klenow's fragment of E. coli DNA polymerase I on the M13mp10 phage DNA as template with synthetic 14-member primer. When the synthesis is terminated by four termination substrates, structure of the synthesised DNA chain can be read. It demonstrates in principle possibility of determination of DNA sequence by means of fluorescence. 相似文献