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   179篇
  免费   2篇
  国内免费   1篇
  182篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2019年   3篇
  2018年   6篇
  2017年   7篇
  2016年   9篇
  2015年   4篇
  2014年   2篇
  2013年   6篇
  2012年   8篇
  2011年   12篇
  2010年   9篇
  2009年   9篇
  2008年   11篇
  2007年   7篇
  2006年   7篇
  2005年   9篇
  2004年   12篇
  2003年   8篇
  2002年   5篇
  2001年   11篇
  2000年   11篇
  1999年   5篇
  1997年   1篇
  1995年   1篇
  1991年   3篇
  1990年   1篇
  1988年   1篇
  1986年   1篇
  1979年   1篇
  1977年   2篇
  1973年   1篇
  1972年   1篇
  1969年   2篇
  1968年   1篇
  1965年   1篇
排序方式: 共有182条查询结果,搜索用时 15 毫秒
61.
62.
Using methods of mathematical statistics the relationships were determined between 31 anthropometric traits (ATs) and the frequency of the X-monosome cell clone in 53 patients with either 45,X-monosomy or mosaic forms (45,X/46,XX) of the Shereshevsky–Turner syndrome (STS). AT variations were studied in patients untreated with growth hormone and in 25 control fertile healthy women. In 29 patients, the degree of mosaicism was assessed by interphase FISH analysis using X-centromer-specific DNA probe hybridized to the cell nuclei of two types of tissues differing in embryonic origin (lymphocytes and oral epithelium, originating from meso- and ectoderm, respectively). The level of X-monosome mosaicism had a substantial effect on some AT, which depended similarly on the proportion of X-monosome cells in tissues of different embryonic origin. Statistically significant negative correlations were revealed between the size of X-monosome clone and 13 height–weight, longitudinal, and circumference traits, whereas positive correlations were characteristic of seven mostly width traits. Eleven ATs showed no correlation with the X-monosome cell clone. Discriminant analysis of all ATs, whose variations depended on the frequency of X-monosome cell clone, was found to be an essential tool for precise classification of both STS patients with different degree of mosaicism and healthy women. Based on these results, the set of ATs characteristic of the STS phenotype was identified.  相似文献   
63.
Physicochemical effects of hydrated C(60) fullerenes (HyFn) on serum albumin molecules were studied using ESR spin labeling and differential scanning microcalorimetry. Molecular-colloidal solution of hydrated C(60) fullerenes and their small spherical fractal clusters in water (C(60)FWS), was shown to stabilize protein hydration, and decrease specific surface energy in water-protein matrix in salt solutions. The mechanism of HyFn interaction with protein is discussed in terms of HyFn induced formation of protein clusters and phase transition of hydration water.  相似文献   
64.
65.
The content of total lipids, total phospholipids, and fatty acids of total lipids in muscles and liver of juvenile Lake Baikal sympatric coregonid fishes have been analyzed for the first time under a common garden experiment. Baikal omul, Coregonus migratorius Georgi, is an active migrant of the pelagic zones of the lake. Baikal (lacustrine) whitefish, C. baicalensis Dybowski, is a colonizer of the bottom habitats, which are relevant to the pelagic zones of the littoral and underwater slope. Structural lipids (phospholipids and cholesterol) dominated in total lipids of the tissues of all fish under study. Spare lipids significantly prevailed in omul muscles when compared to whitefish. The highest variability of fatty acid composition was reported in muscles of coregonid fishes. Statistically significant differences were revealed in the content of the ω3 polyunsaturated fatty acids in muscles of lacustrine whitefish and omul. Associations of lipid compositions revealed in tissues of the whitefishes under the study with their respective ecotypes have been discussed.  相似文献   
66.
Poly(ADP-ribose) polymerase-1 (PARP-1), a nuclear protein of higher eukaryotes, specifically detects strand breaks in DNA. The enzyme is activated in the presence of such breaks and synthesizes poly(ADP-ribose) covalently bound to certain proteins, with PARP-1 itself being the main acceptor. This protein is involved in the majority of DNA-dependent processes, including replication, recombination, repair, and cell death (apoptosis and necrosis). Poly(ADP-ribosyl)ation of proteins is regarded as a mechanism which induces a signal of DNA damage and modulates the function of proteins in response to genotoxic actions. Attention in this review is focused on the role of PARP-1 and poly(ADP-ribosyl)ation in base excision repair (BER), the main process of DNA break repair. The main putative functions of PARP-1 in this process are also considered, namely, its functions as a factor initiating the BER protein complex, a temporary protector of DNA ends, a factor modulating chromatin structure through poly(ADP-ribosyl)ation of histones, and a signal in the mechanism recognizing the degree of DNA damage in the cell.  相似文献   
67.
Expression of channel protein Orai-1 has been demonstrated in cultured skeletal myoblasts and myotubes. In order to evaluate its functional role in Ca2+ transport in these cells we used small interfering RNA (siRNA) targeted against mRNA coding for Orai-1. Optimal conditions for the effective transfection of myoblasts and myotubes were found. In experiments using myotubes from an mdx cell line we have shown that inactivation of mRNA coding Orai-1 results in complete suppression of 45Ca2+ entry induced by thapsigargin, an inhibitor of the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase. The data obtained indicate that Orai-1 is involved in store-activated Ca2+ entry into skeletal myotubes.  相似文献   
68.
Many bacterial secondary metabolites, including pharmacologically promising compounds, are synthesized by polyketide synthases (PKS) enzyme complexes. In the present work, nucleotide sequences of the genes encoding 16S rRNA and PKS of heterotrophic bacterial strains isolated from epilithic biofilms of the littoral zone of Lake Baikal were determined. On the basis of molecular phylogenetic analysis of the 16S rRNA genes, six heterotrophic strains were identified: Serratia fonticola 1А and 10А, Pseudomonas umsongensis K10-2 and K10-3, Rheinheimera tilapiae K18, and Flavobacterium sp. 43-09. Sequencing of cloned amplification products for PKS gene cluster revealed 33 sequences. Genes involved in biosynthesis of antibiotics (difficidine, erythromycin, curacin, mixalamide, corallopyronin, and myxothiazol) and cytostatics (romidepsin, spiruchostatin, and disorazol) were found among homologous sequences. The low homology (50–83%) of the PKS amino acid sequences of Baikal bacteria with sequences from GenBank attests to the potential capability of strains to produce new, not yet studied bioactive compounds. The obtained results show that the studied strains may be of practical interest for biotechnological application.  相似文献   
69.
用蛙胫前肌小束为材料,研究了提高胞外钾[K+]O对咖啡因挛缩的作用。[K+]O从2mmol/L提高到10或25mmol/L,由3mmol/L咖啡因引起的挛缩明显增强。以PKC/PC(PKC和PC分别为在高钾和正常钾条件下的咖啡因挛缩)表示的咖啡因挛缩增强,依赖[K+]O和高钾作用时间。随着10mmol/L[K+]O作用时间延长,直至10min,增强逐渐增加。但是,25mmol/L[K+]O作用1min时增强达到最大,然后下降到对照。PKC/PC变化时程不能用高钾引起的去极化解释,而与由相似[K+]O引起的胞浆自由钙变化时程相符。提示,至少在蛙骨骼肌,高钾引起的咖啡因挛缩增强主要是由胞浆自由钙升高引起的。  相似文献   
70.
Kininogenesis is activated after irradiation as well as after the injection of hydrocortisone. Bradykinin, the main component of the kinin system, is a factor that limits the level of blood plasma 11-oxycorticosteroids after its intravenous injection to exposed rats.  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