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   71篇
  免费   2篇
  2021年   2篇
  2019年   1篇
  2017年   2篇
  2016年   3篇
  2015年   2篇
  2014年   2篇
  2013年   4篇
  2012年   3篇
  2011年   6篇
  2010年   3篇
  2009年   4篇
  2008年   3篇
  2007年   4篇
  2006年   1篇
  2005年   7篇
  2004年   2篇
  2003年   1篇
  2002年   1篇
  2000年   3篇
  1999年   4篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1991年   1篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1981年   1篇
  1969年   2篇
排序方式: 共有73条查询结果,搜索用时 15 毫秒
11.
The in vitro antibacterial and antioxidant activity of the essential oil and its two main components of Grammosciadium scabridum Boiss. (Apiaceae) growing wild in Iran, as well as the composition of its essential oil were studied. A total of 19 compounds representing 99.9% of the oil has been identified. Gamma-Terpinene (73.5%), p-cymene (14.2%) and (E)-beta-farnesene (5.3%) were characterized as the main components. The oil showed remarkable activity against three Gram-negative and four Gram-positive test bacteria, with minimal inhibitory concentration (MIC) values ranging from 0.31 to 10.00 mg/ml. The oil and its two main components were also subjected to screening for their possible antioxidant activity by using the 2,2-diphenyl-l-picrylhydrazyl (DPPH) assay. The free radical scavenging capacity of the oil was determined with an IC50 value of 6.6 mg/ml.  相似文献   
12.
The chemical composition of the essential oils obtained from two samples (GP1 and GP2) of Grammosciadium platycarpum Boiss. was analyzed by GC and GC-MS. The analysis of the oils resulted in the identification of twenty-two constituents. Linalool (79.0%-GP1, 81.8%-GP2) and limonene (10.0%, 5.8%) were found to be the major components, respectively. The in vitro antibacterial activities of these oils and their main compounds against seven Gram-positive and Gram-negative bacteria were investigated. The results exhibited that the total oils and their major components possess strong to moderate activities against all the tested bacteria except for Pseudomonas aeruginosa.  相似文献   
13.
14.
Metabolomics being the most recently introduced "omic" analytical platform is currently at its development phase. For the metabolomics to be broadly deployed to biological and clinical research and practice, issues regarding data validation and reproducibility need to be resolved. Gas chromatography-mass spectrometry (GC-MS) will remain integral part of the metabolomics laboratory. In this paper, the sources of biases in GC-MS metabolomics are discussed and experimental evidence for their occurrence and impact on the final results is provided. When available, methods to correct or account for these biases are presented towards the standardization of a systematic methodology for quantitative GC-MS metabolomics.  相似文献   
15.
16.
Recent advances in cell culture technology have created significant pressure on the downstream purification process, leading to a "downstream bottleneck" in the production of recombinant therapeutic proteins for the treatment of cancer, genetic disorders, and cardiovascular disease. Countercurrent tangential chromatography overcomes many of the limitations of conventional column chromatography by having the resin (in the form of a slurry) flow through a series of static mixers and hollow fiber membrane modules. The buffers used in the binding, washing, and elution steps flow countercurrent to the resin, enabling high-resolution separations while reducing the amount of buffer needed for protein purification. The results obtained in this study provide the first experimental demonstration of the feasibility of using countercurrent tangential chromatography for the separation of a model protein mixture containing bovine serum albumin and myoglobin using a commercially available anion exchange resin. Batch uptake/desorption experiments were used in combination with critical flux data for the hollow fiber filters to design the countercurrent tangential chromatography system. A two-stage batch separation yielded the purified target protein at >99% purity with 94% recovery. The results clearly demonstrate the potential of using countercurrent tangential chromatography for the large-scale purification of therapeutic proteins.  相似文献   
17.
Protein A chromatography is widely employed for the capture and purification of monoclonal antibodies (mAbs). Because of the high cost of protein A resins, there is a significant economic driving force to seek new downstream processing strategies. Membrane chromatography has emerged as a promising alternative to conventional resin based column chromatography. However, to date, the application has been limited to mostly ion exchange flow through (FT) mode. Recently, significant advances in Natrix hydrogel membrane has resulted in increased dynamic binding capacities for proteins, which makes membrane chromatography much more attractive for bind/elute operations. The dominantly advective mass transport property of the hydrogel membrane has also enabled Natrix membrane to be run at faster volumetric flow rates with high dynamic binding capacities. In this work, the potential of using Natrix weak cation exchange membrane as a mAb capture step is assessed. A series of cycle studies was also performed in the pilot scale device (> 30 cycles) with good reproducibility in terms of yield and product purities, suggesting potential for improved manufacturing flexibility and productivity. In addition, anion exchange (AEX) hydrogel membranes were also evaluated with multiple mAb programs in FT mode. Significantly higher binding capacity for impurities (support mAb loads up to 10Kg/L) and 40X faster processing speed were observed compared with traditional AEX column chromatography. A proposed protein A free mAb purification process platform could meet the demand of a downstream purification process with high purity, yield, and throughput. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:974–982, 2015  相似文献   
18.
19.
20.
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