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   176篇
  免费   1篇
  177篇
  2023年   1篇
  2021年   4篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2017年   4篇
  2016年   5篇
  2015年   3篇
  2014年   6篇
  2013年   12篇
  2012年   8篇
  2011年   6篇
  2010年   13篇
  2009年   3篇
  2008年   9篇
  2007年   8篇
  2006年   11篇
  2005年   6篇
  2004年   9篇
  2003年   5篇
  2002年   11篇
  2001年   7篇
  2000年   4篇
  1999年   3篇
  1998年   2篇
  1996年   1篇
  1992年   1篇
  1991年   5篇
  1990年   3篇
  1989年   5篇
  1988年   4篇
  1987年   2篇
  1986年   1篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1979年   1篇
  1976年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
排序方式: 共有177条查询结果,搜索用时 13 毫秒
11.
Concentrations of the total glycogen (TG) and of its labile and stable fractions (LF and SF, respectively) were determined in hepatocytes of portal and central zones of the normal human liver and in the liver of patients with cirrhosis of viral and alcohol etiology. Using the PAS reaction, TG and its LF and SF were revealed in histological sections of the material obtained by liver punction biopsies. Concentrations of TG and its fractions were measured by television cytophotometry. In liver cirrhosis, concentrations of TG, LF, and SF in both zones of the hepatic lobule were much higher than in the normal liver. The ratio between hepatocyte TG concentration in the portal zone and that in the central zone (P/C ratio), both in norm and in viral cirrhosis, exceeds 1.0 to reach, respectively, 1.26 +/- 0.02 and 1.03 +/- 0.01. The glycogen fraction composition in cells of both liver lobule zones in viral cirrhosis does not significantly differ from that in norm. On the contrary, in the liver of patients with alcoholic cirrhosis, the P/C ratio falls to 0.82 +/- 0.02 to be accompanied by qualitative changes in glycogen composition.  相似文献   
12.
Genetic relationships between members of Fagus genus were assessed using ISSR markers and amplification. The taxonomic status of Fagus sylvatica L. and Fagus orientalis LYPSKY. species in Ukraine has been ascertained more precisely. Intraspecies mean genetic distances were compared according to Nei & Li and respective dendrogram was constructed with the complete joining method.  相似文献   
13.
The rate of photosynthetic carbon fixation (P) in the diatom Thalassiosira weissflogii cultivated in the presence of exogenous glucose in the medium (0–10.56 g C/l) at different levels of illumination—25, 50, and 100 E/(m2 s)—was studied as a function of nitrate nitrogen supply. In the diatoms limited in nitrogen and assimilating exogenous glucose, P was found to decrease or increase depending on the light intensity, glucose concentration, and the duration of exposure. In the diatoms assimilating both nitrate nitrogen and glucose, compared to those supplied with nitrates alone, P was higher at the medium and high light intensities and lower at the low light intensity. The interrelation of the processes of carbon and nitrogen metabolism in mixotrophic algae and the ecological role of glucose uptake by phytoplankton are discussed.  相似文献   
14.
By means of light and electron microscopy, the structural pattern of muscle cysts (sarcocysts) was examined for the four species of the genus Sarcocystis: S. muris (from murine skeletal muscles), Sarcocystis sp. and S. fusiformis (from, respectively, heart and skeletal muscles of buffalo), and S. ovifelis (from ovine tong muscles). The orderly fashion of the interior of the cyst is attained by partitition of its space into numerous compartments with the involvement of the intermediate filaments. These, in their turn, are bound to each other by thin filaments to make eventually a common filamentous net. The net limits separate groups of cells referred to as cyst zoites. The common net of filaments and microtubules (when present) may be regarded not only as the organizer of the cyst interior cytoskeleton, but also as the main mechanism of substance transportation in various directions: from the host cell to the sarcocyst, and within or outside the cyst. The role of dedifferentiation, proliferation and differentiation processes is suggested in the establishment of the fixed sequence of events throughout the unidirectional development of cyst cells and their interaction, from precystic meronts to cyst merozoites (gamonts). Special attention is paid to metrocyte morphogenesis and functioning. In the present work, metrocytes subjected to apoptosis were recognized. It is suggested that phenomenon of programmed cell death in metrocytes may be associated with the control of cell number in mature and ageing sarcocysts.  相似文献   
15.
The first analysis of restriction fragment length polymorphism (RFLP) of the mitochondrial gene of cytochrome b of fish from the Eelpout Family (Zoarcidae) from the northern Sea of Okhotsk has been performed. The mean genetic distances between the subfamilies Zoarcinae and Lycodinae, subfamilies Lycodinae and Gymnelinae, and subfamilies Zoarcinae and Gymnelinae are 11.14, 13.87, and 14.00%, respectively. Species of the genus Lycodes (Lycodinae) are characterized by a mtDNA small divergence (on average, 2.04%) and are divided into two groups on the basis of lateral line morphology. Magadania skopetsi, an endemic of Tauiskaya Bay of the Sea of Okhotsk, is genetically close to Hadropareia middendorffii from the same subfamily (Gymnelinae). The mtDNA sequences of species from the genus Lycogrammoides (Lycodinae) differ by 3.83%. The genetic differences between the eelpout Zoarces elongatus Zoarces sp. (d = 4.54%) suggest that the latter is a separate species.  相似文献   
16.
The first analysis of restriction fragment length polymorphism (RFLP) of the mitochondrial gene of cytochrome b of fish from the Eelpout Family (Zoarcidae) from the northern Sea of Okhotsk has been performed. The mean genetic distances between the subfamilies Zoarcinae and Lycodinae, subfamilies Lycodinae and Gymnelinae, and subfamilies Zoarcinae and Gymnelinae are 11.14, 13.87, and 14%, respectively. Species of the genus Lycodes (Lycodinae) are characterized by a mtDNA small divergence (on average, 2.04%) and are divided into two groups on the basis of lateral line morphology. Magadania skopetsi, an endemic of Tauiskaya Bay of the Sea of Okhotsk, is genetically close to Hadropareia middendorffii from the same subfamily (Gymnelinae). The mtDNA sequences of species from the genus Lycogrammoides (Lycodinae) differ by 3.83%. The genetic differences between the eelpout Zoarces elongatus Zoarces sp. (d = 4.54%) suggest that the latter is a separate species.  相似文献   
17.
Chars of the genus Salvelinus, inhabiting lakes and lake-river systems, comprise morphological and ecological forms whose taxonomic status is under dispute. In the present work, we have examined genetic variation and divergence in various chars from the Kronotsky lake basin: the lacustrine chars (white, nose, and longhead) and riverine Dolly Varden Salvelinus malma. The study was conducted using analysis of allozyme and microsatellite loci, myogens, RAPD, and restriction analysis of two mtDNA segments. The estimates of heterozygosity at allozyme and microsatellite loci were similar to the corresponding parameters in populations of northern Dolly Varden and Arctic char. Heterozygote deficit was recorded in both samples of separate forms, and in the total sample of all chars from Kronotsky Lake. For allozyme and microsatellite loci, appreciable genetic differentiation among the samples of different char forms was found, which was comparable to that among the spatially isolated populations of northern Dolly Varden. This result indicates reproductive isolation among the char forms examined. However, this isolation is not complete, because no fixed differences between the forms by any of the genetic systems analyzed were found. The genetic differentiation among different forms of lacustrine chars, which corresponds to the interpopulation rather than interspecific level, is thought to be explained by their comparatively recent divergence.__________Translated from Genetika, Vol. 41, No. 8, 2005, pp. 1096–1107.Original Russian Text Copyright © 2005 by Salmenkova, Omel’chenko, Radchenko, Gordeeva, Rubtsova, Romanov.  相似文献   
18.
19.
Bacteriologic examination of 1589 patients showed that, aside from C. diphtheriae, 11% of acute upper respiratory tract infections were caused by other Corynebacterium species. Such bacteria can cause infections of various localizations (bronchitis, pyelonephritis, urethritis, colpitis, dermatitis, arthritis, etc.). C. pseudodiphtheriticum and C. xerosis were isolated from clinical specimens most frequently. Corynebacterium spp. have adhesive, hemolytic, hemagglutinating, and neuraminidase activity; some of them are highly pathogenic. The most virulent, were following species: C. diphtheriae, C. pseudotuberculosis, C. urealyticum, and C. ulcerans. Corynebacterium non diphtheriae were frequently isolated from clinical specimens in association with staphylococci and streptococci. In such cases, factors of pathogenicity and resistance to antibiotics were more pronounced. Strains isolated with association with other bacteria have lost susceptibility to tetracycline, oleandomycin, penicillin, and erythromycin. It is important to be vigilant about bacteria from Corynebacterium genus in clinical settings, and thoroughly study their biologic characteristics, especially in immunocompromised patients.  相似文献   
20.
The binding of phosphatidylinositol-3,4,5-triphosphate to a protein with molecular mass of 45 kDa from rat olfactory epithelium (p45) was investigated using a model membrane system. Liposomes containing a mixture of phospholipids (phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol-3,4,5-triphosphate) were used in the study. The binding of the protein to liposomes caused by its interaction with phosphatidylinositol-3,4,5-triphosphate was confirmed by cosedimentation and immunoblotting with chemiluminescent detection using monoclonal antibodies to the native protein p45. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2006, vol. 32, no. 3; see also http://www.maik.ru.  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