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   200篇
  免费   15篇
  2022年   2篇
  2021年   8篇
  2020年   10篇
  2019年   9篇
  2018年   6篇
  2017年   10篇
  2016年   10篇
  2015年   18篇
  2014年   18篇
  2013年   18篇
  2012年   18篇
  2011年   13篇
  2010年   3篇
  2009年   6篇
  2008年   15篇
  2007年   10篇
  2006年   9篇
  2005年   8篇
  2004年   7篇
  2003年   5篇
  2002年   6篇
  2000年   1篇
  1998年   2篇
  1989年   1篇
  1980年   1篇
  1971年   1篇
排序方式: 共有215条查询结果,搜索用时 140 毫秒
1.
The distribution of copper and zinc among soluble proteins in liver from normal slaughter cattle was examined after gel filtration of the proteins. Gopper- and zinc-binding proteins were mainly separated into three fractions. Varying amounts of zinc were eluted in a fourth fraction of molecular weight less than 2,000. A clear relationship was noted between the amount of copper bound to the low molecular weight fraction (m.w. ~ 10,000) and the total liver zinc concentration. The high molecular weight protein fraction (m.w. > 65,000) dominated in liver with zinc concentrations below 40 µg/g wet weight and total copper concentrations from 16 to 240 µg/g, while in liver with zinc concentrations above 40 µg/g and copper concentrations ranging from 20 to 107 µg/g, the low molecular weight metallothionein-like fraction dominated.  相似文献   
2.
The original strategies developed by Helicobacter pylori to persistently colonise its host and to deregulate its cellular functions make this bacterium an outstanding model to study host‐pathogen interaction and the mechanisms responsible for bacterial‐induced carcinogenesis. During the last year, significant results were obtained on the role of bacterial factors essential for gastric colonisation such as spiral shape maintenance, orientation through chemotaxis and the formation of bacteria clonal population islands inside the gastric glands. Particularities of the H pylori cell surface, a structure important for immune escape, were demonstrated. New insights in the bacterial stress response revealed the importance of DNA methylation‐mediated regulation. Further findings were reported on H pylori components that mediate natural transformation and mechanisms of bacterial DNA horizontal transfer which maintain a high level of H pylori genetic variability. Within‐host evolution was found to be niche‐specific and probably associated with physiological differences between the antral and oxyntic gastric mucosa. In addition, with the progress of CryoEM, high‐resolution structures of the major virulence factors, VacA and CagT4SS, were obtained. The use of gastric organoid models fostered research revealing, preferential accumulation of bacteria at the site of injury during infection. Several studies further characterised the role of CagA in the oncogenic properties of H pylori, identifying the activation of novel CagA‐dependent pathways, leading to the promotion of genetic instabilities, epithelial‐to‐mesenchymal transition and finally carcinogenesis. Recent studies also highlight that microRNA‐mediated regulation and epigenetic modifications, through DNA methylation, are key events in the H pylori‐induced tumorigenesis process.  相似文献   
3.
BackgroundThe progression of the nonalcoholic fatty liver disease to nonalcoholic steatohepatitis (NASH) is multifactorial, and there is still a lack of approved medications for its treatment. The study aimed to evaluate the impact of combined treatment with Pentoxifylline and Metformin on biochemical parameters in patients with Nash. Setting: Outpatient hepatology clinic.MethodsA prospective trial was conducted. The first cohort included patients with biopsy-proven Nash, while the second cohort consisted of patients with biopsy-confirmed NAFLD. Blood tests were checked at baseline and every three months. Pentoxifylline at a dosage of 400 mg t.i.d. and Metformin at the dosage of 500 mg t.i.d. were introduced for six months in Nash group. The impact of the treatment was assessed based on biochemical results after combined treatment with low-cost medications.ResultsAll 33 Nash patients completed 24 weeks of treatment. We observed significant improvement (p<0.05) of median values after treatment for the following parameters: serum uric acid levels decreased by 51.0 mmol/L, calcium decreased for 0.27 mmoL/L, magnesium showed an increase of 0.11 mmoL/L. Insulin resistance improved as a reduction of HOMA - IR by 1.3 was detected. A significant decrease of median in liver enzymes, alanine aminotransferase, aspartate aminotransferase and gamma-glutamyltransferase by 24.0 U/L, 9.1 U/L, 10.8 U/L respectively, was noted.ConclusionsPentoxifylline and Metformin may provide possible treatment option in Nash. Some new potential benefit of the therapy in improving liver function whilst decreasing cardiovascular risk was perceived.  相似文献   
4.
Molecular Biology Reports - Actinidin (Act d 1), a highly abundant cysteine protease from kiwifruit, is one of the major contributors to the development of kiwifruit allergy. Many studies have...  相似文献   
5.
6.
Dozens of studies have documented that brood parasites are well adapted to a brood parasitic lifestyle but not all parasitism events are successful. Co-evolution between brood parasites and their hosts is a dynamic process so it is reasonable to expect that a female brood parasite may commit errors during egg deposition by laying her eggs outside the laying period of the host, with consequent impacts on her fitness. Using an extensive dataset from a long-term study, we evaluated egg-laying patterns and errors related to the timing of egg-laying in the Common Cuckoo Cuculus canorus (hereafter ‘Cuckoo’). Specifically, we tested whether the Cuckoo avoids laying before or on the day of host clutch initiation to reduce the risk of rejection of parasitic eggs, whether laying errors will be more frequent in periods with a lack of active host nests, and whether the laying errors will be more frequent in periods with intense Cuckoo parasitism and a consequent lack of suitable host nests. We found that about one-third of Cuckoo eggs were laid on the host clutch initiation day or 1 day before, and the percentage of Cuckoo eggs laid decreased thereafter. Surprisingly, the probability of Cuckoo egg acceptance by the hosts was not affected by the egg-laying stage of the host clutch. Errors in the timing of egg-laying with fatal consequences (i.e. those precluding Cuckoo hatching because of laying in incubated or deserted clutches) were recorded in about 5% of cases. Only laying date of a Cuckoo egg had a significant effect on the probability of errors, which increased during the breeding season. This may be related to the higher number of deserted and incubated host nests at the site at the end of the breeding season. Errors in egg-laying may be attributed to young and inexperienced females but also impaired body condition or intraspecific competition may cause this behaviour. Future studies, which will test these possible explanations, will help to understand better the mechanism of co-evolutionary arms races and differences between host specialist and generalist brood parasites in various host–parasite systems.  相似文献   
7.
8.
9.
10.
Aim of the study was to estimate, the relationship between survival, smoking habits, and the results of medical examinations in inland and coastal regions of Croatia. Age and sex stratified sample of general population (1,571 men and 1,793 women, 37-56 years old in 1972; followed in 1982: N = 1,090 men; 1,325 women and/or 1972-1999 controlling vital status). Relative risks and 95% confidence limits were estimated using Cox regression in the model with time dependent covariates, separately by sex. In all regions, the proportion of male smokers decreased between 1972 and 1982. The proportion of female smokers increased, differently in urban and rural regions. During the follow-up between 1972 and 1999, 568 deaths were recorded among men and 382 among women. In men, in addition to age, significant hazards of death were the number of smoked cigarettes per day, body mass index, sedative intake, vital lung capacity (FVC), 100FEV1/VC, systolic blood pressure, electrocardiogram, history of heart attack, and region. In women, in addition to age, significant predictors were the number of smoked cigarettes per day, systolic blood pressure, electrocardiogram, history of heart disease (excluding coronary diseases), and region. Survival relative risk increased with each additional smoked pack of cigarettes by 2.4% in women and 1.3% in men. Regional differences vs. smoking habit were observed. These data emphasize the need for prevention of 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