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   209篇
  免费   17篇
  国内免费   1篇
  227篇
  2023年   4篇
  2022年   15篇
  2021年   22篇
  2020年   6篇
  2019年   6篇
  2018年   8篇
  2017年   6篇
  2016年   21篇
  2015年   12篇
  2014年   21篇
  2013年   12篇
  2012年   14篇
  2011年   10篇
  2010年   7篇
  2009年   4篇
  2008年   11篇
  2007年   8篇
  2006年   8篇
  2005年   10篇
  2004年   8篇
  2003年   6篇
  2002年   5篇
  2000年   2篇
  1995年   1篇
排序方式: 共有227条查询结果,搜索用时 0 毫秒
101.
Bioactive flavonoids and saponins from Climacoptera obtusifolia   总被引:1,自引:0,他引:1  
Two bidesmosidic saponins were isolated from Climacoptera obtusifolia (Chenopodiaceae) and their structures were determined as gypsogenin 3-O-[beta-D-xylopyranosyl-(1-->3)-beta-D-glucopyranoside]-28-O-{beta-D-glucopyranosyl} ester (1) and hederagenin 3-O-[beta-D-xylopyranosyl-(1-->3)-beta-D-glucopyranoside]-28-O-[beta-D-glucopyranosyl} ester (2), by spectroscopic methods. Two known compounds, isorhamnetin 3-O-beta-D-glucopyranoside (3), and isorhamnetin 3-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (4) were also isolated for the first time from this plant. Compounds 1-4 were tested in various immunomodulatory assays. Compound 2 suppressed (92%) the reactive oxygen species (ROS) production on mononuclear cells in luminol-based chemiluminescence (CL) assay at a higher concentration (50 microg/mL). Compounds 3 and 4 demonstrated a strong inhibition on ROS production in the oxidative burst activity of whole blood, neutrophils, and mononuclear cells. Additionally compounds 3 and 4 also suppressed PHA T-cell proliferation with no cytotoxic effects.  相似文献   
102.
The angiotensin converting enzyme gene (ACE) is a candidate gene for an individual's genetic susceptibility to left ventricular hypertrophy (LVH). LVH has long been thought to be an end point of essential hypertension (EH), rather than a separate entity, though it is influenced by a unique set of hormonal, vascular and genetic factors. In this study, we attempted to determine whether two representative polymorphisms of the ACE gene, ACE I/D and 2350 G>A, known to be associated with EH and to influence plasma ACE levels most significantly, could implicate ACE as a quantitative trait locus (QTL) for LVH. We carried out a retrospective, case-control study of the two ACE polymorphisms amongst 180 nationals (50 LVH patients and 130 controls) from the United Arab Emirates--an ethnic group characterized by no alcohol intake and no cigarette smoking--for correlations with LVH. Clinical diagnosis of LVH was based on echocardiographic and ECG criteria. ACE I/D and 2350 G>A genotypes were determined by PCR and restriction digestion. Univariate and multivariate logistic regression analyses revealed an association between ACE polymorphisms and LVH. Haplotype analysis further supported this finding. ACE I/D and ACE 2350 G>A polymorphisms are in strong linkage disequilibrium and are associated with LVH, suggesting that ACE is likely to be a QTL for LVH.  相似文献   
103.
104.
Insomnia is a sleeping disorder, usually studied from a behavioural perspective, with a focus on somatic and cognitive arousal. Recent studies have suggested that an impairment of information processes due to the presence of cortical hyperarousal might interfere with normal sleep onset and/or consolidation. As such, a treatment modality focussing on CNS arousal, and thus influencing information processing, might be of interest. Seventien insomnia patients were randomly assigned to either a tele-neurofeedback (n = 9) or an electromyography tele-biofeedback (n = 8) protocol. Twelve healthy controls were used to compare baseline sleep measures. A polysomnography was performed pre and post treatment. Total Sleep Time (TST), was considered as our primary outcome variable. Sleep latency decreased pre to post treatment in both groups, but a significant improvement in TST was found only after the neurofeedback (NFB) protocol. Furthermore, sleep logs at home showed an overall improvement only in the neurofeedback group, whereas the sleep logs in the lab remained the same pre to post training. Only NFB training resulted in an increase in TST. The mixed results concerning perception of sleep might be related to methodological issues, such as the different locations of the training and sleep measurements.  相似文献   
105.
Evidence from clinical and epidemiological studies indicates that women are disproportionately susceptible to sexually transmitted viral infections. To understand the underlying biological basis for this increased susceptibility, more studies are needed to examine the acute events in the female reproductive tract following exposure to viruses during sexual transmission. The epithelial lining of the female reproductive tract is the primary barrier that sexually transmitted viruses, such as HIV-1 and HSV-2 need to infect or traverse, in order to initiate and establish productive infection. We have established an ex-vivo primary culture system to grow genital epithelial cells from upper reproductive tract tissues of women. Using these cultures, we have extensively examined the interactions between epithelial cells of the female genital tract and HSV-2 and HIV-1. In this review, we describe in detail the experimental protocol to grow these cultures, monitor their differentiation and inoculate with HSV-2 and HIV-1. Prospective use of these cultures to re-create the microenvironment in the reproductive tract is discussed.  相似文献   
106.
107.
108.
Awan  Sliha  Hashmi  Aisha N.  Taj  Rizwan  Munir  Sadaf  Habib  Rabia  Batool  Sajida  Azam  Maleeha  Qamar  Raheel  Nurulain  Syed M. 《Biochemical genetics》2022,60(2):720-737
Biochemical Genetics - Major depressive disorder (MDD) is characterized as clinical depression, which primarily affects the mood and behaviour of an individual. In the present study...  相似文献   
109.
Air-borne fungi at Doha, Qatar   总被引:3,自引:3,他引:0  
Thirty-five genera and 73 species, were identifiedfrom 312 daily exposures set up during theperiod March 1997–March 1998. The total fungalcatch exhibited two peaks in July and December1997 and a trough in February 1998. Cladosporium (6 spp. 40.1% of total fungi),Alternaria (4 spp., 21%) andUlocladium (4 spp., 9.2%) were the maincomponents of air-borne fungi, and thecommonest species were Cladosporium.sphaerospermum (29.7%), C.cladosporioides (6.9%), Alternaria.alternata (13.9%) and U. atrum (5%).The predominance of these dark-coloured fungiin air is discussed and is attributed to one orboth of two hypotheses. Aspergillus (9spp., 4.3%) and Penicillium (8 spp.,3.95%) came next and were represented mainlyby A.niger (1.3%) andP. chrysogenum (2.4%).Spore showers of C.cladosporioides, C. sphaerospermum, Penicillium chrysogenum and Myrotheciumverrucaria were noticed with no regularseasonal pattern.The monthly number of species ranalmost parallel to the total count of fungi.The broadest species spectrum (25–29 spp.) wasrecorded in the summer months May–August 1997and the narrowest (11–12 spp.) in February andMarch 1998.The highest monthly wind velocity wasregularly associated with higher fungal colonycounts than in case of the lowest velocity. Onthe other hand, wind direction did not exhibitany regular correlation either with the colonycounts of fungi or with the wind velocity. Highwind velocity could bring more fungal spores tobe sedimented on the surface of exposed agar.Diurnal fluctuations of fungal spores offungi displayed one peak at 12 noon when thehighest temperature and wind velocity, and theleast relative humidity were recorded and onetrough at midnight.  相似文献   
110.
We previously demonstrated that human platelets activated with SFLLRN release PAR-1 activation peptide, PAR-1-(1-41), even in the presence of hirudin. This observation suggests that during their activation, platelets generate a protease that activates PAR-1. In this study, PAR-1 and -4 activation peptides were detected 10 s after 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