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   45篇
  免费   0篇
  45篇
  2020年   1篇
  2019年   1篇
  2015年   1篇
  2014年   1篇
  2013年   1篇
  2012年   1篇
  2011年   1篇
  2010年   1篇
  2009年   3篇
  2008年   3篇
  2007年   2篇
  2006年   1篇
  2005年   2篇
  2004年   2篇
  2003年   5篇
  2002年   1篇
  2001年   2篇
  2000年   3篇
  1997年   2篇
  1996年   3篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1983年   1篇
  1974年   3篇
  1966年   1篇
排序方式: 共有45条查询结果,搜索用时 9 毫秒
11.
GSTM1 and GSTT1 gene polymorphisms were studied in Shorians, Teleuts, and Caucasians of the Kemerovo region. It has been shown that distribution of homozygous deletions in the examined groups is significantly heterogeneous. The frequency of deletion genotypes and combinations of deletion in these genes was lower in Shorians and, Teleuts than in Caucasians.  相似文献   
12.
The maximum aerobic power and aerobic efficiency (anaerobic threshold) have been determined in major league soccer players. The aerobic capacity of soccer players from leading Russian teams is substantially lower than that of players from leading European teams.  相似文献   
13.
Many structural, signaling, and adhesion molecules contain tandemly repeated amino acid motifs. The alpha-actinin/spectrin/dystrophin superfamily of F-actin-crosslinking proteins contains an array of triple alpha-helical motifs (spectrin repeats). We present here the complete sequence of the novel beta-spectrin isoform beta(Heavy)- spectrin (beta H). The sequence of beta H supports the origin of alpha- and beta-spectrins from a common ancestor, and we present a novel model for the origin of the spectrins from a homodimeric actin-crosslinking precursor. The pattern of similarity between the spectrin repeat units indicates that they have evolved by a series of nested, nonuniform duplications. Furthermore, the spectrins and dystrophins clearly have common ancestry, yet the repeat unit is of a different length in each family. Together, these observations suggest a dynamic period of increase in repeat number accompanied by homogenization within each array by concerted evolution. However, today, there is greater similarity of homologous repeats between species than there is across repeats within species, suggesting that concerted evolution ceased some time before the arthropod/vertebrate split. We propose a two-phase model for the evolution of the spectrin repeat arrays in which an initial phase of concerted evolution is subsequently retarded as each new protein becomes constrained to a specific length and the repeats diverge at the DNA level. This evolutionary model has general applicability to the origins of the many other proteins that have tandemly repeated motifs.   相似文献   
14.
We examine rate heterogeneity among evolutionary lineages of the grass family at two plasmid loci, ndhF and rbcL, and we introduce a method to determine whether patterns of rate heterogeneity are correlated between loci. We show both that rates of synonymous evolution are heterogeneous among grass lineages and that are heterogeneity is correlated between loci at synonymous sites. At nonsynonymous sites, the pattern of rate heterogeneity is not correlated between loci, primarily due to an aberrant pattern of rate heterogeneity at nonsynonymous sites of rbcL. We compare patterns of synonymous rate heterogeneity to predictors based on the generation time effect and the speciation rate hypotheses. Although there is some evidence for generation time effects, neither generation time effects nor speciation rates appear to be sufficient to explain patterns of rate heterogeneity in the grass plastid sequences.   相似文献   
15.
A new drug target - the 'switch region' - has been identified within bacterial RNA polymerase (RNAP), the enzyme that mediates bacterial RNA synthesis. The new target serves as the binding site for compounds that inhibit bacterial RNA synthesis and kill bacteria. Since the new target is present in most bacterial species, compounds that bind to the new target are active against a broad spectrum of bacterial species. Since the new target is different from targets of other antibacterial agents, compounds that bind to the new target are not cross-resistant with other antibacterial agents. Four antibiotics that function through the new target have been identified: myxopyronin, corallopyronin, ripostatin, and lipiarmycin. This review summarizes the switch region, switch-region inhibitors, and implications for antibacterial drug discovery.  相似文献   
16.
Volkov AN  Druzhinin VG 《Genetika》2001,37(9):1296-1299
Long-term cytogenetic monitoring was carried out in adolescents of the town of Kemerovo. In total, aberrant metaphase frequency increased from 1.53% in 1992 to 4.40% in 1996 in Kemerovo adolescents, being significantly higher than a control frequency from 1993 to 1996. In all samples, chromosome aberrations mostly included acentric fragments, while exchanges were rare. The highest number of aberrations per aberrant metaphase was 2 in Kemerovo adolescents and 1 in the control sample. The observed increase in total number of chromosome aberrations suggests that the mutagenic effect of chemical environmental pollutants on Kemerovo adolescents increased over the five years.  相似文献   
17.
18.

Background

Heterogeneity in B-type natriuretic peptide (BNP) levels, especially among individuals with acute heart failure with normal left ventricular ejection fraction (HFNEF), can cause confusion in interpreting results. We investigated the characteristics of cases of acute HFNEF with only modestly elevated BNP.

Methods

One hundred forty-two patients with acute or acute exacerbation of chronic HFNEF were divided into two groups by BNP level: BNP < 100 pg/ml (NB group, n = 45) and BNP ≥ 100 pg/ml (B group, n = 97). We compared clinical findings, echocardiography results, and neurohormonal factors between these two groups.

Results

In the NB group, a history of open-heart surgery (OHS) was more frequent (71% vs. 22%, p < 0.0001) and hypertension was less frequent (p = 0.0005). Left atrial diameter (LAd) was higher (p = 0.0026), while interventricular septal thickness, posterior wall thickness, relative wall thickness, left ventricular mass index were lower (p = 0.0005, p = 0.0225, p = 0.0114, p = 0.0051, respectively) in the NB group. In patients with HFNEF, a history of OHS remained an independent predictor of BNP level (< 100 pg/ml) after adjustment for hypertension, age, LAd, and interventricular septal thickness (odds ratio 3.6, p = 0.0252).

Conclusion

We found associations between acute HFNEF with less elevated BNP and a history of OHS. In a patient suspected of HFNEF, a history of OHS is considered diagnostic evidence of presence of diastolic heart failure when plasma levels of BNP are less elevated.  相似文献   
19.
We present the results of cytogenetic monitoring of the districts in Kemerovo region, which differ in standardized indices of cancer incidence. It has been shown that residents of the districts with high incidence of malignancies had higher average frequency of metaphases with chromosomal aberrations than the control group (4.06 ± 0.12% and 2.76 ± 0.13%, respectively). This difference is caused primarily by single or paired fragments. The increase in the frequency of aberrant metaphase incidence in the districts with elevated cancer frequency was observed both in the male and female groups as well as both in adults and children.  相似文献   
20.
Chromosomal aberration rate has been estimated in peripheral blood lymphocytes of subjects occupationally exposed to a set of hazardous factors (employees of the Kemerovo Heat Power Plant). The frequency of metaphases with aberrations in the workers (3.23 ± 0.26%, N = 104) is significantly higher than in control subjects (2.11 ± 0.28%, N = 70). The cytogenetic aberrations did not depend on the sex, age, duration of employment, or smoking.  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