全文获取类型
收费全文 | 170篇 |
免费 | 6篇 |
出版年
2023年 | 4篇 |
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 11篇 |
2013年 | 11篇 |
2012年 | 12篇 |
2011年 | 12篇 |
2010年 | 8篇 |
2009年 | 9篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 14篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 18 毫秒
51.
Ranjana Sharma Mukesh Jain Raj K. Bhatnagar Neera Bhalla-Sarin 《Physiologia plantarum》1999,105(4):739-745
The multibranched shikimic acid pathway was discovered as the biosynthetic route to the aromatic amino acids phenylalanine, tyrosine and tryptophan and a host of other secondary metabolites. An extensive body of work is available on the characterization of various enzymes of this pathway in order to understand the underlying mechanisms of aromatic amino acid biosynthesis and secondary metabolism in higher plants. In the present investigation, selective assays, based on feedback regulation patterns and divalent cation requirements, were used to monitor the isozyme profiles of two of the key regulatory enzymes of this pathway. 3-Deoxy- d -arabino heptulosonate-7-phosphate synthase (DAHP synthase/DS) (EC 4.1.2.15) and chorismate mutase (CM) (EC 5.4.99.4) have been characterized from different vegetative and reproductive organs of Brassica juncea cv. Pusa Bold. An attempt has also been made to investigate the effect of external factors, such as light and wounding on the regulation of these enzymes. The results reveal differential expression of DAHP synthase and CM in various organs of Brassica and an adaptability of plants to various stresses by up or down regulation of these enzymes. 相似文献
52.
Summary
Bacillus subtilis CD4, when grown in nutrient broth or minimal medium in presence of xylan, produced extracellular xylanase that hydrolyzed xylan optimally at pH 5. The enzyme was induced by xylan, xylose and glucose. Addition of xylose or glucose in xylan containing medium did not affect enzyme production. The structural gene encoding xylanase was cloned and expressed in E. coli. The recombinant enzyme exhibited similar properties like that of native enzyme including resistance to repression by xylose and glucose. 相似文献
53.
Neha Kumari Tripurari Kumar Harsh Arnab S. Bhattacharya Kumar Gaurav Ranjana Verma Sanjoy K. Samdarshi 《Luminescence》2023,38(7):1282-1286
Transition metal oxide has emerged as one of the most potential candidates for environment remediation by utilizing solar energy through photocatalysis. This study compares the optical characteristics of zinc oxide (ZnO) and ceria-doped zinc oxide (CeZnO) nanoparticles synthesized through a facile chemical precipitation method without using any assistant catalyst. The present work investigates the consequences of ceria (cerium dioxide, CeO2) intrusion on the photocatalytic activity of ZnO nanoparticles using methylene blue (MB) as a probe pollutant. The CeZnO showed an increase in photoactivity when compared to ZnO nanoparticles for degradation of MB in an aqueous solution under ultraviolet (UV) irradiance. The resulting heterojunction between ZnO and that of ceria enhances the charge separation efficiency showing a strong correlation between ZnO and CeO2 heterojunction on the charge transfer mechanism across the interface. 相似文献
54.
Panda G Shagufta Mishra JK Chaturvedi V Srivastava AK Srivastava R Srivastava BS 《Bioorganic & medicinal chemistry》2004,12(20):5269-5276
A new series of diaryloxy methano phenanthrenes were prepared through tertiary-aminoalkylations of [(methoxy-phenyl)-phenanthren-9-yl-methyl]-phenols obtained from Friedel-Crafts alkylations on (methoxy-phenyl)-phenanthren-9-yl-methanols. These series of compounds were evaluated against Mycobacterium tuberculosis H37Rv and showed the desired activity in the range of 6.25 microg/mL in vitro. One of the compound 12j protects the mice from the challenge of M. tuberculosis in vivo, as 30% of the mice were survived at treatment of 50 mg/kg body weight. 相似文献
55.
Alexander TW Sharma R Deng MY Whetsell AJ Jennings JC Wang Y Okine E Damgaard D McAllister TA 《Journal of biotechnology》2004,112(3):255-266
The stability of transgenic DNA encoding the synthetic cp4 epsps protein in a diet containing Roundup Ready (RR) canola meal was determined in duodenal fluid (DF) batch cultures from sheep. A real-time TaqMan PCR assay was designed to quantify the degradation of cp4 epsps DNA during incubation in DF at pH 5 or 7. The copy number of cp4 epsps DNA in the diet declined more rapidly (P < 0.05) in DF at pH 5 as compared to pH 7. The decrease was attributed mainly to microbial activity at pH 7 and perhaps to plant endogenous enzymes at pH 5. The 62-bp fragment of cp4 epsps DNA detected by real-time PCR reached a maximum of approximately 1600 copies in the aqueous phase of DF at pH 7, whereas less than 20 copies were detected during incubations in DF at pH 5. A 1363-bp sequence of cp4 epsps DNA was never detected in the aqueous fraction of DF. Additionally, genomic DNA isolated from RR canola seed was used to test the persistence of fragments of free DNA in DF at pH 3.2, 5, and 7, as well as in ruminal fluid and feces. Primers spanning the cp4 epsps DNA coding region amplified sequences ranging in size from 300 to 1363 bp. Free transgenic DNA was least stable in DF at pH 7 where fragments less than 527 bp were detected for up to 2 min and fragments as large as 1363 bp were detected for 0.5 min. This study shows that digestion of plant material and release of transgenic DNA can occur in the ovine small intestine. However, free DNA is rapidly degraded at neutral pH in DF, thus reducing the likelihood that intact transgenic DNA would be available for absorption through the Peyer's Patches in the distal ileum. 相似文献
56.
57.
Impact of feed processing and mixed ruminal culture on the fate of recombinant EPSP synthase and endogenous canola plant DNA 总被引:5,自引:0,他引:5
Alexander TW Sharma R Okine EK Dixon WT Forster RJ Stanford K McAllister TA 《FEMS microbiology letters》2002,214(2):263-269
The impact of feed processing and in vitro ruminal cultures on the persistence of recombinant and canola-specific endogenous DNA was studied using various canola substrates (whole seed, cracked seed, meal and diet). For both, parental and genetically modified substrates, ribulose-1,5-bisphosphate carboxylase/oxygenase gene was amplifiable up to varying time points. Persistence of recombinant DNA, encoding 5-enolpyruvylshikimate-3-phosphate synthase (1,363 bp) was detected up to 8 h for meal and 4 h for mixed diet. Upon processing of canola, DNA large enough to contain intact plant genes remains. In an in vitro environment, plant DNA was rapidly degraded upon its release into rumen fluid. 相似文献
58.
N. Tejo Prakash Neetu Sharma Ranjana Prakash Kuldeep K. Raina Jonathan Fellowes Carolyn I. Pearce Jonathan R. Lloyd Richard A. D. Pattrick 《Biotechnology letters》2009,31(12):1857-1862
The potential of the environment to yield organisms that can produce functional bionanominerals is demonstrated by selenium-tolerant,
aerobic bacteria isolated from a seleniferous rhizosphere soil. An isolate, NS3, was identified as a Bacillus species (EU573774.1) based on morphological and 16S rRNA characterization. This strain reduced Se(IV) under aerobic conditions
to produce amorphous α Se(0) nanospheres. A room-temperature washing treatment was then employed to remove the biomass and
resulted in the production of clusters of hexagonal Se(0) nano-rods. The Se(0) nanominerals were analyzed using electron microscopy
and X-ray diffraction techniques. This Bacillus isolate has the potential to be used both in the neutralizing of toxic Se(IV) anions in the environment and in the environmentally
friendly manufacture of nanomaterials. 相似文献
59.
Deepika Singh Dr. Reema Rani Resmi Rajendran Namrata Jit Kaur Abhinav Pandey Puneet Chopra Tarun Jain Manish Kumar Jain Sonam Grover Ranjana Arya Kulvinder Singh Saini 《Biotechnology journal》2010,5(2):201-212
Spleen tyrosine kinase (Syk) is an important non-receptor tyrosine kinase and its aberrant regulation is associated with a variety of allergic disorders and autoimmune diseases. To identify small molecule inhibitors of Syk in high-throughput assays, recombinant Syk protein is needed in bulk quantity. We studied the expression of recombinant human Syk in three heterologous systems: E. coli, baculovirus expression vector system (BEVS), and the cellular slime mold Dictyostelium discoideum (Dd). Syk activity was higher in the BEVS as compared to the Dd expression host, whereas in E. coli, no activity was observed under our assay conditions. Purified Syk kinase domain protein from BEVS showed concentration dependent inhibition with OXSI-2, a known Syk inhibitor. Molecular modeling and docking studies were performed to understand the binding mode and critical interactions of the inhibitor with catalytic domain of Syk. The BEVS generated Syk kinase domain showed stability upon multiple freeze-thaw cycles and exhibited significantly higher levels of tyrosine phosphorylation at pTyr525/Tyr526 in the Syk activation loop. Based on our data, we conclude that BEVS is the ideal host to produce an active and stable enzyme, which can be successfully employed for screening of Syk inhibitors in a high-throughput system. 相似文献
60.
Supriya Deepak Patil Rajnikant Sharma Santosh Srivastava Naveen Kumar Navani Ranjana Pathania 《PloS one》2013,8(3)