全文获取类型
收费全文 | 479篇 |
免费 | 54篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 2篇 |
综合类 | 20篇 |
化学工业 | 51篇 |
金属工艺 | 2篇 |
机械仪表 | 3篇 |
建筑科学 | 1篇 |
能源动力 | 2篇 |
轻工业 | 445篇 |
水利工程 | 2篇 |
无线电 | 2篇 |
一般工业技术 | 5篇 |
自动化技术 | 4篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 11篇 |
2020年 | 11篇 |
2019年 | 13篇 |
2018年 | 18篇 |
2017年 | 18篇 |
2016年 | 16篇 |
2015年 | 19篇 |
2014年 | 26篇 |
2013年 | 25篇 |
2012年 | 45篇 |
2011年 | 36篇 |
2010年 | 28篇 |
2009年 | 29篇 |
2008年 | 23篇 |
2007年 | 23篇 |
2006年 | 32篇 |
2005年 | 26篇 |
2004年 | 11篇 |
2003年 | 17篇 |
2002年 | 18篇 |
2001年 | 10篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1974年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有539条查询结果,搜索用时 17 毫秒
351.
Fausto Bruno Dos Reis Almeida Laurine Lacerda Pigosso André Ricardo de Lima Damásio Valdirene Neves Monteiro Célia Maria de Almeida Soares Roberto Nascimento Silva Maria Cristina Roque‐Barreira 《Yeast (Chichester, England)》2014,31(1):1-11
The cell wall of Paracoccidioides brasiliensis, which consists of a network of polysaccharides and glycoproteins, is essential for fungal pathogenesis. We have previously reported that N‐glycosylation of proteins such as N‐acetyl‐β‐d ‐glucosaminidase is required for the growth and morphogenesis of P. brasiliensis. In the present study, we investigated the influence of tunycamicin (TM)‐mediated inhibition of N‐linked glycosylation on α‐ and β‐(1,3)‐glucanases and on α‐(1,4)‐amylase in P. brasiliensis yeast and mycelium cells. The addition of 15 µg/ml TM to the fungal cultures did not interfere with either α‐ or β‐(1,3)‐glucanase production and secretion. Moreover, incubation with TM did not alter α‐ and β‐(1,3)‐glucanase activity in yeast and mycelium cell extracts. In contrast, α‐(1,4)‐amylase activity was significantly reduced in underglycosylated yeast and mycelium extracts after exposure to TM. In spite of its importance for fungal growth and morphogenesis, N‐glycosylation was not required for glucanase activities. This is surprising because these activities are directed to wall components that are crucial for fungal morphogenesis. On the other hand, N‐glycans were essential for α‐(1,4)‐amylase activity involved in the production of malto‐oligosaccharides that act as primer molecules for the biosynthesis of α‐(1,3)‐glucan. Our results suggest that reduced fungal α‐(1,4)‐amylase activity affects cell wall composition and may account for the impaired growth of underglycosylated yeast and mycelium cells. © 2013 The Authors. Yeast published by John Wiley & Sons Ltd. 相似文献
352.
R. C. Agu D. L. Devenny I. J. L. Tillett G. H. Palmer 《Journal of the Institute of Brewing》2002,108(2):215-220
Sulphuric acid dehusked barley had a higher germinative energy and lower microbial infection than normal huskless (naked) barley, suggesting that the pericarp layer harboured microbial infection which may have limited the germination rate. Dehusking the normal huskless barley using sulphuric acid resulted in lower microbial infection, and increased germinative energy. The normal huskless barley sample had a higher β‐glucan content than the acid‐dehusked barley and had slower β‐glucan breakdown during malting. This resulted in the release of seven times more β‐glucan during mashing, and the production of wort of higher viscosity. The normal huskless barley sample had a higher total nitrogen content than the acid‐dehusked barley but both samples produced similar levels of amylolytic (α‐ and β‐amylase) activity over the same malting period. No direct correlation was found between barley total nitrogen level and the amylolytic activity of the malt. When barley loses its husk at harvest, the embryo is exposed and may be damaged. This may result in uneven germination which can reduce malting performance and hence malt quality. 相似文献
353.
354.
研究栘叶多酚的大孔吸附树脂纯化工艺,并考察其纯化前后对胰淀粉酶的抑制作用。通过静态吸附解析实验筛选出吸附性能和解吸性能良好的D-101型大孔吸附树脂,进一步研究其纯化多酚的工艺条件和技术参数。结果显示:上样溶液质量浓度为25 mg/m L,上样流速为1 m L/min,以10 BV进行上样,以50%的乙醇溶液为解析剂,洗脱流速为3 m L/min,洗脱体积为8 BV进行洗脱,栘叶浸膏中多酚的含量由原来的39.7%提高到91.89%。纯化后,栘叶多酚对胰淀粉酶的抑制率高于纯化前,且纯化前后对胰淀粉酶的抑制率均高于100 mg/m L大黄提取物对胰淀粉酶的抑制效果,说明栘叶多酚对胰淀粉酶有明显的抑制效果,且纯化有利于提高栘叶多酚对胰淀粉酶的抑制作用。 相似文献
355.
356.
解淀粉芽孢杆菌可用作多种食品工业酶的生产菌株,但其极低的转化效率影响了这类工业菌株的重组改造及优化。通过对1398解淀粉芽孢杆菌和一种地衣芽孢杆菌Jbac基因组的数据分析,发现这些微生物存在IV型DNA限制修饰系统。对这些微生物转化经甲基化和未经甲基化的质粒,证实外源DNA甲基化修饰会降低DNA的转化效率;利用将外源质粒进行相同类型甲基化的这种新转化策略,表达质粒pMK4E-dx被转入解淀粉芽孢杆菌LT中,发酵结果显示,其中重组菌株LT-J1/pMK4-dx和LT-J2/pMK4-dx分泌的中温淀粉酶活达到145.9和153.6 U/mL,分别为原菌株发酵淀粉酶活的3.65和3.84倍。 相似文献
357.
可可粉在饮料中不稳定,可以通过酶的作用降低可可粉的粒径,改善可可粉的溶解性。分别用淀粉酶、纤维素酶、蛋白酶、木聚糖酶对可可粉进行处理,发现淀粉酶、纤维素酶对可可粉有较强的作用,蛋白酶对可可粉几乎没有作用,木聚糖酶和纤维素酶、淀粉酶协同作用才有效果。通过正交实验得到酶解的最佳工艺是:在可可粉的天然pH下,加入0.5%(w/w)的淀粉酶、2%(w/w)的纤维素酶,0.2%(w/w)的木聚糖酶,在50℃下作用4h。 相似文献
358.
该文研究了耐盐米曲霉制曲的产酶特性,并且通过对耐盐米曲霉在不同作用条件下制得的曲料的蛋白酶活力和淀粉酶活力的变化分析,探讨了不同原料配比、水分添加量、制曲温度和蒸料时间等因素对耐盐米曲霉制曲效果的影响,为米曲霉在工业生产中的研究和应用提供理论依据.研究表明,耐盐米曲霉制曲产生的中性蛋白酶和碱性蛋白酶的酶活较高,酸性蛋白酶和淀粉酶酶活较低.复合酶分泌的最佳工艺条件为:原料配比为豆粕:麸皮=2:3,加水量为120%,蒸料时间为30min,30℃制曲42h,此条件下酸性蛋白酶和淀粉酶活力有明显的提高. 相似文献
359.
Gobinath Rajagopalan Chandraraj Krishnan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(11):1511-1517
BACKGROUND: A malto‐oligosaccharide forming α‐amylase from Bacillus subtilis KCC103 immobilized in calcium alginate beads was repeatedly used in batch processes of starch hydrolysis. The degree of starch degradation and operational stability of the immobilized system were optimized by varying the physical characteristics and composition of the beads. The products formed from hydrolysis of various starches by α‐amylase immobilized in different supports were analyzed. RESULTS: Immobilized beads prepared from 3% (w/v) alginate and 4% (w/v) CaCl2 were suitable for up to 10 repeated uses, losing only 25% of their efficiency. On addition of 1% silica gel to alginate prior to gelation, the operational stability of the immobilized enzyme was enhanced to 20 cycles of operation, retaining > 90% of the initial efficiency. Distribution of malto‐oligosaccharides in the starch hydrolyzate depended on the type of starch, reaction time and mode of immobilization. Soluble starch and potato starch formed a wide range of malto‐oligosaccharides (G1–G5). Starches from wheat, rice and corn formed a narrow range of smaller oligosaccharides (G1–G3) as the major products. CONCLUSION: The immobilized beads of α‐amylase from KCC103 prepared from alginate plus silica gel showed high efficiency and operational stability for hydrolysis of starch. This immobilized system is useful for production of malto‐oligosaccharides applied in the food and pharmaceutical industries. Since this KCC103 amylase can be produced at low cost utilizing agro‐residues in a short time and immobilized enzyme can be recycled, the overall cost of malto‐oligosaccharide production would be economical for industrial application. Copyright © 2008 Society of Chemical Industry 相似文献
360.
Gobinath Rajagopalan Chandraraj Krishnan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(5):654-661
BACKGROUND: In Bacillus subtilis KCC103 α‐amylase is hyper‐produced and not catabolite repressed by glucose. Various sugars, raw starches and nitrogen sources were tested for their repression effect on α‐amylase synthesis. Enhancement of α‐amylase production by supplementing micronutrients and surfactants was studied. Using optimized medium, process parameters were optimized for improved α‐amylase production. RESULTS: α‐Amylase was produced from KCC103 utilizing simple sugars indicating the absence of catabolite repression. Raw potato and yeast extract were best carbon and nitrogen sources for α‐amylase production. α‐Amylase synthesis was enhanced by micronutrients cysteine, thiamine, Mg2+ and SDS. Maximum α‐amylase (394 IU mL?1) was produced in the optimized medium consisting of (in g L?1) raw potato (30.0), yeast extract (20.0), cysteine (0.3), thiamine (0.2), SDS (0.2) and MgSO4 (0.5 mmol L?1) at 36–48 h under optimal conditions (pH 7.0, 37 °C, 200 rpm). The α‐amylase production was further enhanced to 537.7 IU mL?1 with shorter time (15–18 h) in a bioreactor with optimized agitation rate of 700 rpm at 30% dissolved oxygen. CONCLUSION: Since there was no carbon catabolite repression of α‐amylase synthesis, sugar mixture from various agro‐residues hydrolysates could be utilized for α‐amylase production. The study showed the feasibility of utilization of raw potato for α‐amylase production from the KCC103, which would lead to a significant reduction in process cost. Copyright © 2008 Society of Chemical Industry 相似文献