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   130篇
  免费   9篇
  2023年   4篇
  2022年   4篇
  2021年   9篇
  2020年   1篇
  2019年   1篇
  2018年   3篇
  2017年   8篇
  2016年   5篇
  2015年   4篇
  2014年   6篇
  2013年   10篇
  2012年   10篇
  2011年   12篇
  2010年   8篇
  2009年   10篇
  2008年   5篇
  2007年   13篇
  2006年   7篇
  2005年   7篇
  2004年   4篇
  2003年   2篇
  2002年   2篇
  1993年   1篇
  1989年   1篇
  1983年   1篇
  1971年   1篇
排序方式: 共有139条查询结果,搜索用时 109 毫秒
71.
This paper provides a review of the current status and historical distribution of Lobotes surinamensis in the Mediterranean Sea. Thirty two records were compiled for the period between 1968 and 2016, which shows that the species is in the Mediterranean much more abundant than previously understood.  相似文献   
72.
Glutathione reductase (E C: 1.8.1.7; GR) was purified from rainbow trout (Oncorhynchus mykiss) liver, and some characteristics of the enzyme were investigated. The purification procedure consisted of four steps: preparation of homogenate, ammonium sulfate fractionation, affinity chromatography on 2',5'-ADP Sepharose-4B and gel filtration chromatography on Sephadex G-200. The enzyme, with a specific activity of 27.45 U/mg protein, was purified 1,654-fold with a yield of 41%. Optimal pH, stable pH, optimal temperature, optimum ionic strength, molecular mass, KM and Vmax values for GSSG and NADPH were also determined for the enzyme. In addition, Ki values and inhibition types were determined for GSH and NADP+. Additionally, inhibitory effects of metal ions (Cd+2, Cu+2, Pb+2, Hg+2, Fe+3 and Al+3) on glutathione reductase were investigated. Ki constants and IC50 values for metal ions were determined by Lineweaver-Burk graphs and plotting activity % vs. [I], respectively. IC50 values of Cd+2,Cu+2, Pb+2, Hg+2, Fe+3 and Al+3 were 0.0655, 0.082, 0.122, 0.509, 0.797 and 0.804 mM, and the Ki constants for Cd+2 and Cu+2 were 0.104+/-0.001, 0.117+/-0.001, respectively.  相似文献   
73.
74.
Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are the key enzymes in pathogenesis of Alzheimer's disease (AD), which is characterized by a deficit in central cholinergic transmission. In the current study, AChE and BChE inhibitory activities of seven coumarin derivatives [umbelliferone (1), 4-methylumbelliferone (2), 4-hydroxycoumarin (3), scopoletin (4), 8-methoxypsoralen (5), bergapten (6), and iso-bergapten (7)], a furanocoumarin mixture obtained from Heracleum crenatifolium Boiss. (Umbelliferae), as well as of two anthroquinone derivatives [rhein (8) and aloe-emodine (9)] and one stilbene, rhapontin (10), were tested by the spectrophotometric method of Ellman using an ELISA microplate-reader at 1 mg mL(-1). Among them, the furanocoumarin mixture [(68.8 +/- 0.76)%], bergapten [(62.4 +/- 0.74)%], aloe-emodine [(57.2 +/- 1.32)%], scopoletin [(53.1 +/- 0.83)%], and 4-methylumbelliferone [(62.3 +/- 1.03)%] showed over 50% inhibition against AchE, while umbelliferone [(54.3 +/- 0.23)%], 4-methylumbelliferone [(80.9 +/- 1.17)%], scopoletin [(73.5 +/- 1.01)%], 8-methoxypsoralen [(67.1 +/- 0.98)%], as well as the furanocoumarin mixture [(76.7 +/- 0.95)%] had a notable anti-BChE effect.  相似文献   
75.
We have tested acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of nineteen essential oils obtained from cultivated plants, namely one from Anethum graveolens L. (organic fertilizer), two from Foeniculum vulgare Mill. collected at fully-mature and flowering stages (organic fertilizer), two from Melissa officinalis L. (cultivated using organic and chemical fertilizers), two from Mentha piperita L. and M. spicata L. (organic fertilizer), two from Lavandula officinalis Chaix ex Villars (cultivated using organic and chemical fertilizers), two from Ocimum basilicum L. (green and purple-leaf varieties cultivated using only organic fertilizer), four from Origanum onites L., O. vulgare L., O. munitiflorum Hausskn., and O. majorana L. (cultivated using organic fertilizer), two from Salvia sclarea L. (organic and chemical fertilizers), one from S. officinalis L. (organic fertilizer), and one from Satureja cuneifolia Ten. (organic fertilizer) by a spectrophotometric method of Ellman using ELISA microplate-reader at 1 mg/ml concentration. In addition, a number of single components widely encountered in most of the essential oils [gamma-terpinene, 4-allyl anisole, (-)-carvone, dihydrocarvone, (-)-phencone, cuminyl alcohol, cumol, 4-isopropyl benzaldehyde, trans-anethole, camphene, iso-borneol, (-)-borneol, L-bornyl acetate, 2-decanol, 2-heptanol, methyl-heptanol, farnesol, nerol, iso-pulegol, 1,8-cineole, citral, citronellal, citronellol, geraniol, linalool, alpha-pinene, beta-pinene, piperitone, iso-menthone, menthofurane, linalyl oxide, linalyl ester, geranyl ester, carvacrol, thymol, menthol, vanilline, and eugenol] was also screened for the same activity in the same manner. Almost all of the essential oils showed a very high inhibitory activity (over 80%) against both enzymes, whereas the single components were not as active as the essential oils.  相似文献   
76.
Four lignan type compounds, lariciresinol, taxiresinol, isolariciresinol and 3-demethyl-iso-lariciresinol, were isolated from the heartwood of Taxus baccata L. (Taxaceae) growing in Turkey through chromatographic techniques. In vivo anti-ulcerogenic potency of these compounds was investigated on ethanol-induced ulcerogenesis model in rats at two different doses, 50 and 100 mg/kg. All compounds were shown to possess significant anti-ulcerogenic activity at both doses. However, the effect of taxiresinol was the most prominent.  相似文献   
77.
The aim of this study is to determine the relation between diabetes and vaginal candidiasis in terms of oxidative biomarker levels in a vaginal candidiasis model of the diabetic rats by evaluating malondialdehyde (MDA), sulphydrile groups or glutathione (RSH), and ascorbic acid (C vit) levels. All rats were randomly divided into five groups. All of the groups were observed for 21 days. In the treated diabetes groups, MDA (0.90, 0.68 nmol/ml and 3.78, 3.79 nmol/g tissue, plasma and vaginal tissue, respectively) and RSH (227, 171 nmol/100 ml 0.38, 0.37 μmol/g tissue, plasma and vaginal tissue, respectively) levels were found to be decreased while the levels of C vit were found to be increased (0.49, 0.37 μmol/l 2.39, 2.01 nmol/g tissue plasma, and vaginal tissue, respectively) (P < 0.05). In the groups of untreated diabetes, vaginal candidiasis were found to be more serious and oxidative biomarkers were found to be increased (MDA 1.30, 1.26 nmol/ml and 7.82, 2.37 nmol/g tissue and RSH 258, 145 nmol/100 ml and 0.31, 0.46 μmol/g tissue) while the antioxidant C vit levels were found to be decreased (0.24, 0.17 μmol/l 1.33, 2.66 nmol/g tissue) (P < 0.05). RSH, plasma MDA, blood glucose, and tissue MDA levels of vaginal candidiasis embedeled diabetic rats, were found to be higher than those in untreated diabetic and untreated vaginitis enbedeled rats ‹P < 0.05’. Vaginal candidiasis caused oxidative stress in diabetic rats working together. Systemic oxidative stress biomarkers were found to be affected from vaginal candidiasis although it was a local mucosal infection. This study was presented as a poster in the conference of ‹2nd Trends in Medical Mycology, 23–26 October 2005, Berlin, Germany’.  相似文献   
78.
Alzheimer's disease (AD), the most common form of dementia, is a neurodegenerative disease characterized by progressive cognitive deterioration together with declining activities of daily living and neuropsychiatric symptoms or behavioural changes. The oldest, on which most currently available drug therapies are based, is known as the "cholinergic hypothesis" and suggests that AD begins as a deficiency in the production of the neurotransmitter acetylcholine. Therefore, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors have gained a great popularity for the treatment of AD. In this study, we screened in vitro inhibitory activities of a number of phenolic acids (chlorogenic, caffeic, gallic, and quinic acids) as well as of various flavonoid derivatives (genistein, biochanin A, naringin, apigenin, quercetin, luteolin-7-O-rutinoside, kaempferol-3-O-galactoside, diosmin, silibinin, and silymarin) against AChE and BChE at 1 mg/ml concentration using a microplate-reader assay based on the Ellman method. Among them, only quercetin showed a substantial inhibition (76.2%) against AChE, while genistein (65.7%), luteolin-7-O-rutinoside (54.9%), and silibinin (51.4%) exerted a moderate inhibition on BChE.  相似文献   
79.
80.
We present a novel study on label-free recognition and distinction of drug resistant breast cancer cells (MCF-7 DOX) from their parental cells (MCF-7 WT) via impedimetric measurements. Drug resistant cells exhibited significant differences in their dielectric properties compared to wild-type cells, exerting much higher extracellular resistance (Rextra). Immunostaining revealed that MCF-7 DOX cells gained a much denser F-actin network upon acquiring drug resistance indicating that remodeling of actin cytoskeleton is probably the reason behind higher Rextra, providing stronger cell architecture. Moreover, having exposed both cell types to doxorubicin, we were able to distinguish these two phenotypes based on their substantially different drug response. Interestingly, impedimetric measurements identified a concentration-dependent and reversible increase in cell stiffness in the presence of low non-lethal drug doses. Combined with a profound frequency analysis, these findings enabled distinguishing distinct cellular responses during drug exposure within four concentration ranges without using any labeling. Overall, this study highlights the possibility to differentiate drug resistant phenotypes from their parental cells and to assess their drug response by using microelectrodes, offering direct, real-time and noninvasive measurements of cell dependent parameters under drug exposure, hence providing a promising step for personalized medicine applications such as evaluation of the disease progress and optimization of the drug treatment of a patient during chemotherapy.  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