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排序方式: 共有72条查询结果,搜索用时 46 毫秒
1.
Clara A. Ferraz Dr. Nicole G. H. Leferink Iaroslav Kosov Prof. Dr. Nigel S. Scrutton 《Chembiochem : a European journal of chemical biology》2021,22(13):2325-2334
Linalool is a monoterpenoid used as a fragrance ingredient, and is a promising source for alternative fuels. Synthetic biology offers attractive alternative production methods compared to extraction from natural sources and chemical synthesis. Linalool/nerolidol synthase (bLinS) from Streptomyces clavuligerus is a bifunctional enzyme, producing linalool as well as the sesquiterpenoid nerolidol when expressed in engineered Escherichia coli harbouring a precursor terpenoid pathway such as the mevalonate (MVA) pathway. Here we identified two residues important for substrate selection by bLinS, L72 and V214, where the introduction of bulkier residues results in variants with reduced nerolidol formation. Terpenoid production using canonical precursor pathways is usually limited by numerous and highly regulated enzymatic steps. Here we compared the canonical MVA pathway to the non-canonical isopentenol utilization (IU) pathway to produce linalool using the optimised bLinS variant. The IU pathway uses isoprenol and prenol to produce linalool in only five steps. Adjusting substrate, plasmid system, inducer concentration, and cell strain directs the flux towards monoterpenoids. Our integrated approach, combining enzyme engineering with flux control using the artificial IU pathway, resulted in high purity production of the commercially attractive monoterpenoid linalool, and will guide future efforts towards efficient optimisation of terpenoid production in engineered microbes. 相似文献
2.
Bao-Qing Zhu Jian Cai Zhi-Qun Wang Xiao-Qing Xu Chang-Qing Duan Qiu-Hong Pan 《International journal of molecular sciences》2014,15(12):21992-22010
Monoterpenoids are a diverse class of natural products and contribute to the important varietal aroma of certain Vitis vinifera grape cultivars. Among the typical monoterpenoids, linalool exists in almost all grape varieties. A gene coding for a nerolidol/linalool (NES/LINS) synthase was evaluated in the role of linalool biosynthesis in grape berries. Enzyme activity assay of this recombinant protein revealed that it could convert geranyl diphosphate and farnesyl diphosphate into linalool and nerolidol in vitro, respectively, and thus it was named VvRILinNer. However, localization experiment showed that this enzyme was only localized to chloroplasts, which indicates that VvRILinNer functions in the linalool production in vivo. The patterns of gene expression and linalool accumulation were analyzed in the berries of three grape cultivars (“Riesling”, “Cabernet Sauvignon”, “Gewurztraminer”) with significantly different levels of monoterpenoids. The VvRILinNer was considered to be mainly responsible for the synthesis of linalool at the early developmental stage. This finding has provided us with new knowledge to uncover the complex monoterpene biosynthesis in grapes. 相似文献
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Mohsen Gavahian Asgar Farahnaky Mahsa Majzoobi Katayoun Javidnia Mohammad Jamal Saharkhiz Gholamreza Mesbahi 《International Journal of Food Science & Technology》2011,46(12):2619-2627
Ohmic‐assisted hydrodistillation (OAHD) is a combination of ohmic heating and distillation, and could be considered as a novel method for the extraction of essential oils. Major problems with traditional methods are long extraction time and lower purity of the extract. In this study, OAHD was applied as an economic and green technology for the extraction of essential oils from Zataria multiflora Boiss. (Shirazi thyme) aerial parts and the results were compared to those obtained from hydrodistillation (HD) as a conventional method. The results showed that OAHD method had the extraction time of 32.21 ± 2.59 min while this value was about 57.21 ± 2.33 min for hydrodistillation (HD). Scanning electron micrographs of thyme leaves showed a sudden eruption of essential oil glands and their surrounding area for OAHD samples. GC–MS analysis indicated that both methods of OAHD and HD can extract the same compounds. 相似文献
5.
脱氢芳樟醇选择性加氢合成芳樟醇 总被引:1,自引:0,他引:1
研究制备了负载型双金属Pd-Bi/Al2O3催化剂,用于固定床中脱氢芳樟醇选择性加氢生成芳樟醇的反应。考察了催化剂中活性组分Pd的负载量,以及在不同反应温度下Pd与Bi的原子配比对反应活性和选择性的影响。实验结果表明,当催化剂中Pd负载量为0.6‰,Pd/Bi原子比为1,在反应温度90℃和反应压力1.5MPa时,反应转化率为95.7%,生成芳樟醇的选择性达到85.3%。 相似文献
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去氢芳樟醇加氢在机械搅拌釜中进行,采用膜分离设备,实现了催化剂在反应系统中循环使用,大大提高了催化剂使用寿命:考察了反应温度、压力对加氢反应结果的影响;提出了反应终点预测方法. 相似文献
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蒎烷氧化反应机理及动力学研究 总被引:1,自引:0,他引:1
分别推导了单分子退化支化引发和双分子退化支化引发时的动力学模型,并根据实验数据对两种模型进行了分析。结果表明:在蒎烷氧化反应中,认为单分子退化支化引发为主的模型假设是合理的,根据这一机理,建立了相应的动力学模型,并由实验得到了相关的动力学参数。 相似文献
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对少花桂叶的香气活性成分进行分析鉴定。采用顶空固相微萃取制备样品,用两根色谱柱(极性柱DB-WAX和弱极性柱DB-5)进行气相色谱-质谱联用分析,并用DB-5柱进行直接强度法气相色谱-嗅闻分析(GC-O),基于保留指数、质谱库检索、气味特征鉴定化合物。结果:共鉴定出88种挥发性成分,含量高(>1%)的成分为芳樟醇、香豆素、δ-杜松烯、檀香萜、α-古巴烯、苯乙烯、β-檀香萜、反式肉桂醛、乙酸龙脑酯和1, 8-桉叶油素等。检测到23种化合物有气味活性,按照气味强度,对总体香气贡献大(香气强度值≥ 3)的为反式肉桂醛、芳樟醇、4-萜品醇、乙酸龙脑酯、β-檀香萜和肉桂酸乙酯,研究结果为少花桂的开发应用提供基础。 相似文献