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   99篇
  免费   5篇
  2019年   2篇
  2018年   3篇
  2017年   1篇
  2016年   1篇
  2015年   1篇
  2014年   1篇
  2013年   5篇
  2012年   10篇
  2011年   10篇
  2010年   4篇
  2009年   5篇
  2008年   6篇
  2007年   6篇
  2006年   1篇
  2005年   6篇
  2004年   3篇
  2003年   5篇
  2002年   3篇
  2001年   2篇
  2000年   5篇
  1999年   4篇
  1998年   2篇
  1997年   2篇
  1995年   2篇
  1993年   3篇
  1991年   1篇
  1988年   1篇
  1985年   2篇
  1983年   1篇
  1982年   2篇
  1977年   1篇
  1970年   1篇
  1966年   2篇
排序方式: 共有104条查询结果,搜索用时 109 毫秒
31.
Kamishoyosan (KSS), a Kampo formula used to treat menopausal psychotic syndromes in women, consists of ten crude herbal drugs. The anxiolytic effect of KSS was investigated by the social interaction (SI) test using mice, and whether the effect of KSS was due to the stimulating and/or sedating effects was examined by the open field locomotion test. Furthermore, the present study examined the effect of individual crude drugs in KSS by the SI test to clarify its active components. Oral administration of KSS increased the total SI time in a dose-dependent manner (50--200 mg/kg), but this effect was not observed over a dose of 300 mg/kg. On the other hand, there were no significant changes observed for the open field locomotion test. These results suggest that the appearance of KSS-induced SI behavior is due to an anxiolytic effect. The unaltered results of the open field test indicated that KSS was neither a stimulant nor sedative. To identify the essential herbs in KSS, the effects of "the component herbs in KSS" and "KSS minus one component herb" using the SI test were examined. An increase in the SI time was observed for hot water extracts of Menthae herba and Gardeniae Fructus, the same as for the KSS treatment. On the other hand the effect of KSS on the SI time was reduced to the control level for KSS minus Gardeniae Fructus, KSS minus Paeoniae Radix, KSS minus Glycyrrhizae Radix and KSS minus Hoelen. Oral administration of Gardeniae Fructus-extract or its common constituent, geniposide increased the SI time in a dose-dependent manner. These results indicate that Gardeniae Fructus and geniposide play a role in the anxiolytic effect of KSS.  相似文献   
32.
33.
1. Several bacteria were isolated from soil which grew on both d- and l-aminolactam and whose cells had an activity to racemize them. They were identified as Achromobacter obae nov. sp., Achr. cycloclastes, Alcaligenes faecalis and Flavobacterium arborescens.

2. Racemization of d- and l-aminolactam was investigated using the lyophilized cells of Achr. obae nov. sp. The optimum pH value of the reaction was about 8.0. The racemizing activity was completely inhibited by 10?4 m hydroxylamine, and the inhibition was removed by 10?4 m pyridoxal phosphate. Five percent d- and l-aminolactam solutions were completely racemized with a concomitant slight formation of l-lysine.  相似文献   
34.
The marine red alga genus Laurencia is one of the richest producers of unique brominated compounds in the marine environment. The cDNAs for two Laurencia nipponica vanadium-dependent bromoperoxidases (LnVBPO1 and LnVBPO2) were cloned and expressed in Escherichia coli. Enzyme assays of recombinant LnVBPO1 and LnVBPO2 using monochlorodimedone revealed that they were thermolabile but their Km values for Br? were significantly lower than other red algal VBPOs. The bromination reaction was also assessed using laurediol, the predicted natural precursor of the brominated ether laurencin. Laurediol, protected by trimethylsilyl at the enyne, was converted to deacetyllaurencin by the LnVBPOs, which was confirmed by tandem mass spectrometry. Native LnVBPO partially purified from algal bodies was active, suggesting that LnVBPO is functional in vivo. These results contributed to our knowledge of the biosynthesis of Laurencia brominated metabolites.  相似文献   
35.
Sorafenib (Nexavar, BAY43-9006, 1) is a second-generation, orally active multikinase inhibitor that is approved for the treatment of some cancers in patients. In this Letter, we developed [11C]1 as a novel positron emission tomography (PET) probe, and evaluated the influence of ABC transporters-mediated efflux on brain uptake using PET with [11C]1 in P-glycoprotein (P-gp)/breast cancer resistance protein (Bcrp) knockout mice versus wild-type mice. [11C]1 was synthesized by the reaction of hydrochloride of aniline 2 with [11C]phosgene ([11C]COCl2) to give isocyanate [11C]6, followed by reaction with another aniline 3. Small-animal PET study with [11C]1 indicated that the radioactivity level (AUC0-60 min, SUV × min) in the brains of P-gp/Bcrp knockout mice was about three times higher than in wild-type mice.  相似文献   
36.
The purpose of this study was to develop 4-[18F]fluoro-N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methylbenzamide ([18F]FITM, [18F]4) as a new PET ligand for imaging metabotropic glutamate receptor subtype 1 (mGluR1). [18F]4 was synthesized by [18F]fluorination of a novel nitro precursor 3 with [18F]KF in the presence of Kryptofix 222. At the end of synthesis, 429-936 MBq (n = 8) of [18F]4 was obtained with >99% radiochemical purity and 204-559 GBq/μmol specific activity starting from 6.7 to 13.0 GBq of [18F]F. The brain distribution of [18F]4 was determined by the in vitro and ex vivo autoradiography using rat brain sections. The in vitro and in vivo specific binding of [18F]4 to mGluR1 was detected in the cerebellum, thalamus, hippocampus, and striatum. These results suggest that [18F]4 is a promising PET ligand for the in vivo evaluation of mGluR1.  相似文献   
37.
Radiation and Environmental Biophysics - Folic acid (FA) has high affinity for the folate receptor (FR), which is limited expressed in normal human tissues, but over-expressed in several tumor...  相似文献   
38.
Monomeric Kusabira Orange (mKO) is a green fluorescent protein (GFP)-like protein that emits orange light at a peak of 559 nm. We analyzed its X-ray structure at 1.65 A and found a novel three-ring chromophore that developed autocatalytically from a Cys65-Tyr66-Glu67 tripeptide in which the side chain of Cys65 formed the third 2-hydroxy-3-thiazoline ring. As a result, the chromophore contained the CNCOH group at the 2-position of the imidazolinone moiety such that the conjugated pi-electron system of the chromophore was more extended than that of GFP but less extended than that of the Discosoma sp. red fluorescent protein (DsRed). Since a sulfur atom has potent nucleophilic character, the third 3-thiazoline ring is rapidly and completely cyclized. Furthermore, our structure reveals the presence of a pi-pi stacking interaction between His197 and the chromophore as well as a pi-cation interaction between Arg69 and the chromophore. These structural findings are sufficient to account for the orange emission, pH tolerance, and photostability of mKO.  相似文献   
39.
Comparative sequence analyses have identified highly conserved genomic DNA sequences, including noncoding sequences, between humans and other species. By performing whole-genome comparisons of human and mouse, we have identified 611 conserved noncoding sequences longer than 500 bp, with more than 95% identity between the species. These long conserved noncoding sequences (LCNS) include 473 new sequences that do not overlap with previously reported ultraconserved elements (UCE), which are defined as aligned sequences longer than 200 bp with 100% identity in human, mouse, and rat. The LCNS were distributed throughout the genome except for the Y chromosome and often occurred in clusters within regions with a low density of coding genes. Many of the LCNS were also highly conserved in other mammals, chickens, frogs, and fish; however, we were unable to find orthologous sequences in the genomes of invertebrate species. In order to examine whether these conserved sequences are functionally important or merely mutational cold spots, we directly measured the frequencies of ENU-induced germline mutations in the LCNS of the mouse. By screening about 40.7 Mb, we found 35 mutations, including mutations at nucleotides that were conserved between human and fish. The mutation frequencies were equivalent to those found in other genomic regions, including coding sequences and introns, suggesting that the LCNS are not mutational cold spots at all. Taken together, these results suggest that mutations occur with equal frequency in LCNS but are eliminated by natural selection during the course of evolution.  相似文献   
40.
Normalization of tumor vasculature is an emerging strategy to improve cytotoxic therapies. Here we show that eliminating nitric oxide (NO) production from tumor cells via neuronal NO synthase silencing or inhibition establishes perivascular gradients of NO in human glioma xenografts in mice and normalizes the tumor vasculature, resulting in improved tumor oxygenation and response to radiation treatment. Creation of perivascular NO gradients may be an effective strategy for normalizing abnormal vasculature.  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