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   56篇
  免费   2篇
  国内免费   3篇
  2024年   1篇
  2021年   4篇
  2020年   1篇
  2019年   2篇
  2018年   1篇
  2017年   3篇
  2014年   2篇
  2013年   2篇
  2012年   5篇
  2011年   3篇
  2010年   3篇
  2009年   3篇
  2008年   1篇
  2007年   6篇
  2006年   3篇
  2005年   4篇
  2004年   6篇
  2003年   3篇
  2001年   1篇
  1999年   1篇
  1997年   1篇
  1996年   1篇
  1993年   1篇
  1989年   1篇
  1987年   1篇
  1984年   1篇
排序方式: 共有61条查询结果,搜索用时 187 毫秒
31.
在漫长的历史中,中国的医药学家对粪便类药物持续不断地在进行研究,尤其是在过去的几百年间积累了越来越多的经验,是中国传统医药学极其宝贵的财富。应用粪便类药辨治疾病是中医诊疗特色之一。广泛而丰富的临床治疗信息为现代医学积累了大量的诊疗依据和启示,尤其是目前的粪菌移植治疗研究,它拓展了粪便类中药治疗的新概念,明确其疗效机制乃至为新产品的研发提供依据。现代微生态学的发展也为祖国医学的研究带来了新的契机和前景。  相似文献   
32.
The feeding niches and trophic ecology of two South African grazers, blue wildebeest Connochaetes taurinus and black wildebeest Connochaetes gnou, are compared using stable carbon and nitrogen isotope data from feces and tooth dentine collagen. As sympatric, closely related taxa predicted to occupy similar trophic positions, the blue and black wildebeest provide a good model for studying the mechanisms of coexistence and macroevolution in mammals. Data from feces collected from a single reserve in the Free State Province reveal different trophic behaviors between two herds of blue wildebeest and between both compared with a single herd of black wildebeest. These data suggest that sympatric coexistence of blue and black wildebeest is facilitated by differential niche occupation at family group or herd levels, rather than between species. However, such separation does not occur over longer time scales: results from dentine collagen support the hypothesis that the two species are indistinct in terms of trophic behavior, although blue wildebeest show more feeding flexibility, probably because of their wider habitat tolerance range. Similarities in premaxillary width of males and females of both species also suggest that both species are adapted to similar feeding styles. Thus, it is unlikely that changes in trophic behavior provided the trigger for divergence of the black from the blue wildebeest lineage in the Middle Pleistocene. We argue that the case of these two species represents an example of speciation that was not driven by resource competition, as is often assumed for many turnover events in mammalian evolution. We briefly discuss a previous suggestion that links black wildebeest evolution to their more territorial breeding behavior associated with Middle-to-Late Pleistocene landscape changes in southern Africa.  相似文献   
33.
5′-Nuclease and a hybridization probe assays for the detection of shiga toxin-producing Escherichia coli were validated with regard to selectivity, analytical sensitivity, reproducibility and clinical performance. Both assays were capable of detecting the classical stx1 and stx2 genes when challenged with reference strains of E. coli (n = 40), although 1 to 4 minority sequence variants, whose clinical relevance is limited (stx1c, stx1d, and stx2f), were detected less efficiently or not at all by one or both assays. No cross reaction was observed for both assays with 37 strains representing other gastrointestinal pathogens, or normal gastrointestinal flora. Analytical sensitivity ranged from 3.07 to 3.52 log10 and 3.42 to 4.63 log10 CFU/g of stool for 5′-nuclease and hybridization probe assay, respectively. Reproducibility was high with coefficients of variation of ≤ 5% for both inter- and intra-assay variation. Clinical performance was identical with a panel of archived positive specimens (n = 19) and a prospective panel of stools associated with bloody diarrhea (n = 115). In conclusion, both assays proved to be sensitive and reproducible.  相似文献   
34.
肠球菌TaqMan实时荧光定量PCR检测方法的建立及初步应用   总被引:1,自引:0,他引:1  
目的利用TaqMan荧光定量PCR方法,建立肠球菌实时荧光PCR检测方法,并初步应用于粪便中肠球菌的检测。方法根据GenBank发表的肠球菌23S rRNA基因序列的保守区域参考国外文献设计合成特异性的引物和探针[1];利用构建的质粒标准品优化Mg2 的浓度和引物探针浓度,并考核检测体系的保守性、灵敏性和重复性;初步应用于粪便标本的检测分析。结果Mg2 终浓度为4.5 mmol/L,上下游引物终浓度为0.4μmol/L,灵敏度为6拷贝数/反应;绘制两种标准曲线,构建了基因拷贝数、细菌数为分析指标的定量分析模型,检测粪便标本结果显示TaqMan荧光定量PCR方法较平板计数法敏感、快捷、简便。结论本研究建立了一种灵敏、特异、简便易行的肠球菌定量检测方法。  相似文献   
35.
Because of overpopulation of African elephants in South Africa and the consequent threat to biodiversity, the need for a method of population control has become evident. In this regard, the potential use of the porcine zona pellucida (pZP) vaccine as an effective means for population control is explored. While potential effects of pZP treatment on social behavior of African elephants have been investigated, no examination of the influence of pZP vaccination on the endocrine correlates in treated females has been undertaken. In this study, ovarian activity of free-ranging, pZP-treated African elephant females was monitored noninvasively for 1 yr at Thornybush Private Nature Reserve, South Africa, by measuring fecal 5α-pregnan-3β-ol-20-on concentrations via enzyme immunoassay. A total of 719 fecal samples from 19 individuals were collected over the study period, averaging 38 samples collected per individual (minimum, maximum: 16, 52). Simultaneously, behavioral observations were made to record the occurrence of estrous behavior for comparison. Each elephant under study showed 5α-pregnan-3β-ol-20-on concentrations rising above baseline at some period during the study indicating luteal activity. Average 5α-pregnan-3β-ol-20-on concentrations were 1.61 ± 0.46 μg/g (mean ± SD). Within sampled females, 42.9% exhibited estrous cycles within the range reported for captive African elephants, 14.3% had irregular cycles, and 42.9% did not appear to be cycling. Average estrous cycle duration was 14.72 ± 0.85 wk. Estrous behavior coincided with the onset of the luteal phase and a subsequent rise in 5α-pregnan-3β-ol-20-on concentrations. Average 5α-pregnan-3β-ol-20-on levels positively correlated with rainfall. No association between average individual 5α-pregnan-3β-ol-20-on concentrations or cyclicity status with age or parity were detected. Earlier determination of efficacy was established via fecal hormone analysis with no pregnancies determined 22 mo post-treatment and onward. Results indicate the presence of ovarian activity amongst pZP-treated female African elephants in 2 yr after initial immunization. Further study should now be aimed toward investigating the long-term effects of pZP vaccination on the reproductive function of female African elephants.  相似文献   
36.
目的探讨浙江大学医学院第一附属医院住院患者肠道真菌分离状况与趋势变化。方法回顾分析2000年1月1日至2009年12月30日10年间在该院送检的住院患者粪便标本的真菌分离率、真菌种类和年度变迁变化特点。结果 10年间从送检全部疑似肠道真菌感染的2 344份粪便标本中共检到真菌1 456株,归属5属19种,每年的检出率在55.7%67.0%。分离菌株中以白色念珠菌(74.0%)占首位,其次是光滑念珠菌(11.4%),再次是热带念珠菌(7.1%),光滑念珠菌和热带念珠菌分离率分别从2000年的4.9%、6.6%上升到2009年的16.8%、10.6%,呈上升趋势。结论该院10年间肠道真菌的分离率较高,白色念珠菌的分离率一直位于首位,非白色念珠菌的分离率处于上升趋势。  相似文献   
37.
摘要 目的:探讨与分析粪便中双歧杆菌和大肠杆菌含量对肝癌患者预后的预测价值。方法:研究时间为2016年12月到2019年12月,采用回顾性研究方法,选择在本院重症监护病房(Intensive Care Unit,ICU)诊治的肝癌患者78例作为研究对象,检测粪便中双歧杆菌和大肠杆菌含量,调查患者的预后并进行预测价值分析。结果:在78例患者中,死亡18例,死亡率为23.1 %。存活组与死亡组的性别、年龄、体重指数、白细胞(white blood cell,WBC)、血小板(Platelets,PLT)计数计数等对比差异无统计学意义(P>0.05),两组的急性生理学及慢性健康状况评分系统(acute physiology andchronic health evaluation scoring system,APACHE Ⅱ)评分、临床分期等对比差异有统计学意义(P<0.05),死亡组的血清甲胎蛋白(?琢-fetoprotein,AFP)值显著高于存活组(P<0.05)。死亡组的双歧杆菌含量与双歧杆菌/大肠杆菌比值低于存活组,大肠杆菌含量高于存活组,对比差异都有统计学意义(P<0.05)。直线相关分析显示患者预后死亡与双歧杆菌/大肠杆菌比值、AFP、APACHE Ⅱ评分、临床分期有相关性(P<0.05)。双歧杆菌/大肠杆菌比值对肝癌患者预后死亡的预测ROC曲线下总面积为0.865。结论:肝癌患者预后死亡患者多伴随有粪便中菌群失衡状况,粪便中双歧杆菌和大肠杆菌含量能很好预测肝癌患者的预后。  相似文献   
38.
Non-invasive methods to measure steroid hormone metabolites in bird droppings or mammalian feces have become very popular. However, the accuracy of these measurements may be affected by many factors. Here, we use the stonechat (Saxicola torquata) as a passerine bird model to test whether differences in ambient temperature affect food intake and dropping production and whether these changes lead to measurement artefacts in hormone metabolite concentrations. In addition, we tested for diurnal patterns in hormone metabolites. We held European stonechats in climate chambers and subjected them to two different long-term ambient temperature regimes, +5 degrees C and +22 degrees C. As expected, food intake and dropping production was higher at +5 degrees C than at +22 degrees C. Plasma concentrations of corticosterone and testosterone did not differ between different ambient temperature regimes. However, corticosterone and testosterone metabolite concentrations (in ng/g) were significantly lower at +5 degrees C than at +22 degrees C. When we measured the rate of hormone metabolite excretion (in picogram per hour) instead of the concentration, there was no difference between treatment groups. Thus, the measurement of hormone metabolite concentrations can be flawed because, depending on the treatment, similar amounts of hormone metabolites can be excreted into very different amounts of droppings. In conclusion, hormone metabolite concentration measurements are sensitive to changes in ambient temperature and probably any other factor that alters metabolic rates. Any study involving systematic changes in metabolism--i.e., during molt, migration, hibernation, egg production, or seasonal comparisons--needs to take these caveats into account.  相似文献   
39.
Aquatic crustaceans often play a major role in organic matter (OM) transformation and recycling through their feeding and excretory activities. In this study, we measured the isotopic and elemental composition of organic matter fed to Palaemonetes sp. shrimp and the fecal pellets they produced. Nitrogen (N) content of the food (8.2 ± 0.2%, mean ± SD) was significantly higher than the fecal pellets (2.0 ± 0.9%), a pattern that also applied to the carbon (C) content of food (46.7 ± 1.0%) and fecal pellets (14.3 ± 6.8%). We also found a significant decrease in the N content of undigested, macerated food (6.1 ± 0.9 %) relative to food that had been soaked in artificial seawater (ASW) and artificial seawater that had previously contained shrimp (CASW) in the absence of feeding shrimp. We found no significant difference in N or C isotopic composition between the dry food, ASW- and CASW-soaked control food, and fecal pellets. We did, however, observe a significant increase in δ15N of the undigested, macerated food (δ15= 6.3 ± 0.6‰) relative to both the dry flake food (δ15= 5.6 ± 0.2‰) and controls incubated in the absence of shrimp in either ASW (δ15N = 5.6 ±0.3‰) or CASW (δ15N = 5.8 ± 0.1‰). Our results differ from previous findings of isotopic alteration of OM during processing by crustaceans (copepods), suggesting that isotopic changes related to feeding might be either taxon- or food-specific. This study also provides information on the influence of grazers/shredders on both the elemental and isotopic composition of POM, suggesting that larger aquatic shredders can influence the chemical composition of particles by either physical manipulation of the POM (release of DOM) or by facilitating microbial colonization of the POM.  相似文献   
40.
In this article, we describe a simple, sensitive, accurate, and repeatable method for the measurement of phenol and p-cresol (4-methylphenol) in human urine and feces. We examined a number of parameters to identify an optimal extraction protocol. Purification of sample extracts was achieved by low-temperature vacuum microdistillation. Separation was achieved in approximately 15 min by high-performance liquid chromatography (HPLC) with quantification by fluorescence at 284/310 nm. Limits of detection for phenol were 2 ng/ml for urine and 20 ng/g for feces, and those for p-cresol were 10 ng/ml for urine and 100 ng/g for feces. For comparison, approximate mean values for urine are 3 μg/ml for phenol and 30 μg/ml for p-cresol, and those for feces are 1 μg/g for phenol and 50 μg/g for p-cresol. An experienced analyst can process 60 samples each day using this method.  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