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   54篇
  免费   0篇
  2017年   1篇
  2016年   2篇
  2014年   2篇
  2013年   2篇
  2012年   1篇
  2011年   1篇
  2010年   1篇
  2009年   2篇
  2008年   3篇
  2007年   2篇
  2006年   3篇
  2005年   8篇
  2004年   3篇
  2003年   3篇
  2002年   1篇
  2001年   3篇
  2000年   1篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1989年   1篇
  1988年   1篇
  1985年   1篇
  1984年   2篇
  1982年   1篇
  1979年   2篇
  1975年   1篇
  1974年   1篇
  1972年   1篇
排序方式: 共有54条查询结果,搜索用时 15 毫秒
1.
2.
The eutrophic effect of products of vital activity of colonies of hydrophilic birds on the community of heterotrophic plankton in shallow parts of the plain reservoir is shown. The strongest effect of birds is observed in a protected part of the reservoir. Specific changes in some characteristics of zooplankton as distinct from the response to the anthropogenic effect are found.  相似文献   
3.
Interactions of the main components of microbial planktonic food web (bacteria, heterotrophic nanoflagellates, and viruses) were studied in a protected overgrown littoral zone of the Rybinsk Reservoir (Upper Volga). The effect of colonial bird settlements (the Laridae family) on these processes was determined. The following systems exhibited significant negative correlations: “heterotrophic nanoflagellates–large rod-shaped bacteria” (“predator–prey”), “viruses-bacteriophages–bacterial products” (“parasite–host”) and “heterotrophic nanoflagellates–viruses-bacteriophages”. Relations between biotic factors controlling bacterial development were more pronounced outside the zone affected by colonial bird settlements. Near the bird colony the role of viruses in mortality of planktonic bacteria increased. Reproduction of bacterial cells accelerated in response to the increase in feeding activity of heterotrophic nanoflagellates. Virusesbacteriophages and heterotrophic nanoflagellates probably eliminate different targets until medium-sized cells become predominant in the bacterial community. Then heterotrophic nanoflagellates consume bacterial cells infected with viruses.  相似文献   
4.
In this report, we describe three unrelated patients with similar symptoms such as mental retardation, growth delay and multiple phenotypic abnormalities. GTG-banding analysis revealed karyotypes with add(1p) in two cases and an add(1q) in the third. Fluorescence in situ hybridization (FISH) analysis using high resolution multicolor banding (MCB) characterized the aberrations of the abnormal chromosomes 1 as a (sub)terminal duplication and inverted duplications, respectively. Although three different chromosomal regions i.e. 1p36.1, 1p36.2-->1p31.3 and 1q41-->1q44 were involved, all three patients had similar patterns of dysmorphic findings. These cases demonstrate the power of MCB in the characterization of small interstitial chromosomal aberrations and resulted in the characterization of three previously unreported congenital chromosome 1 rearrangements.  相似文献   
5.
Arabinogalactan proteins (AGPs) are highly glycosylated hydroxyproline-containing variously located proteoglycans dynamically regulated in the course of plant ontogenesis. Special functions of AGPs are still unclear, but their involvement in vegetative growth and reproduction of plants is well established. This review considers data on the structure, biosynthesis, and metabolism of AGPs. Special attention is given to involvement of AGPs in growth and morphogenesis, and possible mechanisms of their regulatory action are considered. AGPs are also compared with animal proteoglycans.  相似文献   
6.
The pathogenesis of cataract is associated with oxidative stress and with altered crystallin expression but it is still understood incompletely. In this study, the senescence-accelerated OXYS rats were used as a model. The first biomicro-scopic signs of cataract in OXYS rats were registered at the age of 1.5 months; at 3 months morbidity reached 90%, and at 6 months it reached 100%. Cataract manifestation progresses: at 24 months mature cataract was detected in 90% of eyes of OXYS rats, whereas in 80% of Wistar rat eyes only initial signs of this disease were detected. Analysis of lens redox-parameters has shown that in OXYS rats the intensity of tryptophan fluorescence is higher, the GSH content being higher at 2 months but during formation of mature cataract at 13, 18, and 24 months being lower than in Wistar rats. Decrease in solubility of OXYS rat lens proteins was observed at the age of 13 months. At the age of 3 months gene expression of αA-crystallin and αB-crystallin was 3-fold and 25% lower, respectively, than in Wistar rats. At the age of 14 months there was a 27-fold decrease in expression of αB-crystallin in OXYS rats and it became 21-fold lower than in control. Proteins are synthesized in lens epithelial cells and dystrophic changes in senile cataract result in decrease in structural protein expression. The changes observed in OXYS rats are evidently associated with the dystrophic changes in lens epithelium, which we have described earlier, and are consistent with the model of senile cataract.  相似文献   
7.
Methods of synthesis of coproporphyrin and uroporphyrin by using bacteria of the genus Arthrobacterare proposed. Metal complexes of coproporphyrin and uroporphyrin with Pt, Pd, and Zn were synthesized. Their structures were identified by spectrophotometry, IR spectrometry, 1H-NMR, mass spectrometry, and HPLC. Data showing the possibility of using coproporphyrin III–metal complexes as luminophores for fluorescence detection of tumors was gathered. The current and prospective uses of metal complexes of water-soluble natural porphyrins in advanced immunofluorescence assays are discussed.  相似文献   
8.
9.
10.
It is shown that the inhibitor of catalase 3-amino-1,2,4-triazole (AT) at the concentration of 2 mM affected differently growth of tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) callus lines differing in the morphogenecity. In some cases, AT induced the death of a great fraction of non-morphogenic callus cells; in other cases, it inhibited growth and reduced viability of morphogenic callus. The death of non-morphogenic callus cells may be related to the accumulation of hydrogen peroxide and the development of oxidative stress. After morphogenic callus treatment with AT, we obtained a modified line 1?C8 AT tolerant to AT and differing from the original line in morphology, cell sizes, proliferative activity, and some biochemical characteristics. In the 1?C8 AT line, catalase was sensitive to this inhibitor action. In this case, catalase inactivation with AT did not increase the content of hydrogen peroxide in the cells, which may indicate the compensatory functioning of another/others mechanism(s) destroying hydrogen peroxide.  相似文献   
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