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   152篇
  免费   8篇
  160篇
  2023年   2篇
  2022年   6篇
  2021年   12篇
  2020年   8篇
  2019年   20篇
  2018年   11篇
  2017年   9篇
  2016年   7篇
  2015年   8篇
  2014年   11篇
  2013年   7篇
  2012年   13篇
  2011年   17篇
  2010年   6篇
  2009年   1篇
  2008年   1篇
  2007年   6篇
  2006年   2篇
  2005年   2篇
  2004年   3篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  1999年   2篇
  1966年   1篇
排序方式: 共有160条查询结果,搜索用时 15 毫秒
11.
PurposeIt has been suggested that nitric oxide (NO) has a role in ischemic retinopathies. Since retinal ischemia may develop in retinal vein occlusion, we investigated the presence of nitric oxide in the pathogenesis of central retinal vein occlusion (CRVO).MethodsEighteen consecutive patients with CRVO were included in this study. Aqueous humor specimens were obtained within 21 days of diagnosis. Samples of aqueous humor were also collected from 20 control patients undergoing cataract surgery. For each sample after reduction of nitrate to nitrite with vanadium chloride (VCl3), we used spectrophotometric method for simultaneous detection of nitrate and nitrite (NOx).ResultsMean level of aqueous humor NOx in CRVO and control group was 94.1 ± 23.2 μmol/l and 55.6 ± 11.0 μmol/l, respectively. The difference between two groups was statistically significant (p < 0.0001).ConclusionsOur results may support involvement of nitric oxide in the pathogenesis of CRVO.  相似文献   
12.
Calprotectin (CP) is widely considered to have diverse roles including growth inhibitory and apoptosis induction in a number of tumor cell lines and antimicrobial activities. As CP has been proposed to bind metal ions with high affinity, we have studied its functional and primarily its structural behavior upon Zn2+ and Mn2+ chelation solely and along with Ca2+. We employed fluorescence spectroscopy and circular dichroism to determine the resulting modifications. Based upon our findings it is clear that treating CP with ions effectively weakened its natural growth inhibitory activity. Moreover, structural analysis of Zn2+ and Mn2+-treated CPs indicated remarkable alterations in the regular secondary structures in favor of irregular structures while Zn2+ and Mn2+ treatment of CP after incubation with Ca2+ displayed no remarkable shifts. Tertiary structure investigation using fluorescence spectroscopy showed that CP undergoes conformational changes upon Zn2+ and Mn2+ treatment whereby Trp residues of protein is slightly exposed to the hydrophilic environment, compactness of CP is compromised, whereas in Ca2+-treated CP, the tertiary structure integrity is intact upon Zn2+ and Mn2+ chelation. Interestingly, CP structural modifications upon Zn2+ and Mn2+ treatment was significantly comparable, probably due to similar radii and charges of ions. Taken all together, we have concluded that CP maintains its normal nature in Ca2+-loaded state when treated with Zn2+ and Mn2+ ions. It can be suggested that Ca2+ not only stabilize CP structure but also helps CP to keep its structure upon metal ions chelation which is involved in host organism defense system.  相似文献   
13.
International Journal of Peptide Research and Therapeutics - RADA 16-I is an amphiphilic peptide which can form macroscopic scaffolds through self-assembly and has found many applications in tissue...  相似文献   
14.
In farmed rainbow trout Oncorhynchus mykiss, the flagellate Spironucleus salmonis (Diplomonadida) is often found in the pyloric region of the intestine. While previous in vitro studies report a pH of 7.5 to 8.0 as optimal for presumed S. salmonis, no previous in vivo studies have investigated the relationship between pH and microhabitat preference. Therefore, in 698 rainbow trout (75% were 5 to 6 mo old juveniles, 10 to 20 cm total length), we recorded occurrence and density of S. salmonis, and pH, in the pyloric, anterior, middle, and posterior intestine. There were no significant differences in total length or weight between infected and uninfected fish. S. salmonis preferred the pyloric region, with occurrence and density decreasing significantly from pyloric to posterior regions. In infected fish, pH in pyloric (6.8 to 7.9, mean 7.3) and posterior regions (6.5 to 8.0, mean 7.1) was significantly lower than in anterior (6.5 to 8.5, mean 7.7) and middle (6.8 to 8.2, mean 7.7) regions; in uninfected fish, the pH profile was similar. At the individual level, 90 % of infected fish and 79% of uninfected fish showed this pH profile. In the pyloric region, pH was not significantly different among uninfected fish, and fish with light, moderate, or heavy infections. Our in vivo study suggests the optimal pH for S. salmonis is between 7.1 and 7.5, possibly close to 7.3 (the mean in pyloric region of infected fish). We conclude that while the presence of S. salmonis reflected tolerable pH, density of infection was not correlated with pH, and thus a causal relationship between microhabitat preference and pH is unlikely.  相似文献   
15.
Air movement preferences observed in office buildings   总被引:1,自引:0,他引:1  
Office workers’ preferences for air movement have been extracted from a database of indoor environmental quality surveys performed in over 200 buildings. Dissatisfaction with the amount of air motion is very common, with too little air movement cited far more commonly than too much air movement. Workers were also surveyed in a detailed two-season study of a single naturally ventilated building. About one-half the building’s population wanted more air movement and only 4% wanted less. This same ratio applied when the air movement in workspaces was higher than 0.2 m/s, the de facto draft limit in the current ASHRAE and ISO thermal environment standards. Preference for “less air motion” exceeded that for “more” only at thermal sensations of −2 (cool) or colder. These results raise questions about the consequences of the ASHRAE and ISO standards’ restrictions on air movement, especially for neutral and warm conditions.  相似文献   
16.
Two hundred and seventy nine patients suspected of having fungal lesions were examined. Skin scrapping, hair samples and nail clippings were collected from patients. Direct and culture examinations were performed for all samples. About 115 cases of examined subjects had dermatophytosis. Dermatophytosis occurred mainly in adults males (20–29 years). Tinea cruris (24.3%) was the most common type of dermatophytosis followed by tinea pedis (16.5%), tinea corporis (14.8%), tinea ungium (13%), tinea capitis (11.3%), tinea faciei (11.3%), tinea manuum (7%) and tinea barbae (1.7%). Trichophyton mentagrophytes was the most prevalent species followed by Epidermophyton floccosum.  相似文献   
17.
Lithium preparations are commonly used drug in treating mental disorders and bipolar diseases, but metal's cytotoxic mechanisms have not yet been completely understood. In this study, we investigated the cytotoxic mechanisms of lithium in freshly isolated rat hepatocytes. Lithium cytotoxicity were associated with reactive oxygen species (ROS) formation and collapse of mitochondrial membrane potential and cytochrome c release into the hepatocyte cytosol. All of the mentioned lithium-induced cytotoxicity markers were significantly (P?相似文献   
18.
Kidney pain is one of the clinically significant features of renal dysfunction. Mild to severe pain is seen in the lower back area. Painkillers are mostly recommended in these cases to relieve the symptom. Yet, several analgesics are associated with side effects that can worsen the state of the disease. This review is based on the studies conducted in these aspects analgesics used to treat kidney pain and their effectiveness, renal consequences of postoperative analgesia, and pharmacogenetics of these palliatives are briefly summarized in this paper.  相似文献   
19.
International Journal of Peptide Research and Therapeutics - Query fever is an important disease caused by Coxiella burnetii, therefore vaccination against this disease is so crucial. Com1 is one...  相似文献   
20.
Because of the effect of photoperiod on physiological and biochemical processes in fish, this study aimed to evaluate the effect of manipulated photoperiod on growth, feed conversion and survival of wild carp, Cyprinus carpio. Fish received six photoperiod regimes (light:dark cycle) including: natural photoperiod (control), 24L:0D, 16L:8D, 12L:12D, 8L:16D and 0L:24D by the three replications. Regulated photoperiods as a 16L:8D or 12L:12D light/dark cycle significantly improved growth rate and food conversion ratio of wild carp.  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