全文获取类型
收费全文 | 464篇 |
免费 | 37篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 4篇 |
综合类 | 23篇 |
化学工业 | 106篇 |
金属工艺 | 3篇 |
机械仪表 | 25篇 |
建筑科学 | 16篇 |
矿业工程 | 4篇 |
能源动力 | 10篇 |
轻工业 | 186篇 |
水利工程 | 2篇 |
石油天然气 | 4篇 |
无线电 | 24篇 |
一般工业技术 | 13篇 |
原子能技术 | 3篇 |
自动化技术 | 86篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 19篇 |
2014年 | 25篇 |
2013年 | 18篇 |
2012年 | 21篇 |
2011年 | 40篇 |
2010年 | 39篇 |
2009年 | 43篇 |
2008年 | 38篇 |
2007年 | 35篇 |
2006年 | 41篇 |
2005年 | 34篇 |
2004年 | 15篇 |
2003年 | 18篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 11篇 |
1999年 | 5篇 |
1998年 | 14篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有509条查询结果,搜索用时 21 毫秒
11.
目的:以小黄鱼内脏精炼鱼油为原料,通过脂肪酶选择性水解法富集二十碳五烯酸(eicosapentaenoic acid,EPA)甘油酯和二十二碳六烯酸(docosahexaenoic acid,DHA)甘油酯。方法:采用气相色谱峰面积外标法定量测定EPA和DHA甘油酯总含量。通过单因素和响应面试验,考察反应时间、pH值、反应温度、加酶量等因素对富集效果的影响。结果:确定最佳工艺条件为反应时间4 h、pH 8.0、反应温度30 ℃、加酶量1.0%,在此条件下,EPA和DHA甘油酯总含量为21.65%,且4 个因素对EPA和DHA甘油酯富集的影响依次增强。结论:富集后鱼油理化指标和感官评价均优于精炼鱼油,EPA和DHA甘油酯总含量是富集前的1.74 倍,获得了天然的EPA和DHA甘油酯。 相似文献
12.
Abdulkadir Bayr H brahim Halilolu A Necdet Sirkeciolu N Mevlüt Aras 《Journal of the science of food and agriculture》2006,86(1):163-168
The muscle fatty acid (FA) composition of 12 selected marine fish species living in Turkish waters was determined. FA profiles of muscle were compared in terms of total and individual saturated (SFAs) and unsaturated fatty acids. Total SFA, monounsaturated fatty acid (MUFA), n‐3 polyunsaturated fatty acid (n‐3 PUFA) and n‐6 polyunsaturated fatty acid (n‐6 PUFA) contents as well as n‐3/n‐6 FA and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) ratios differed (P < 0.01) in all fish species. Palmitic acid (16:0) among total SFAs, oleic acid (18:1n‐9) among MUFAs, DHA (22:6n‐3) among n‐3 PUFAs and 18:2n‐6 and 20:4n‐6 among n‐6 PUFAs were the most abundant FAs. The ratio of n‐3/n‐6 PUFA contents, indicating the availability of n‐3 PUFAs that are beneficial for human health, ranged from 2.67 to 12.61. The EPA/DHA ratio was between 0.17 and 0.83 in the marine fish species studied. Copyright © 2005 Society of Chemical Industry 相似文献
13.
采用气相色谱法对海洋鱼油软胶囊中脂肪酸组成和比率进行分析,为合理补充DHA、EPA等多不饱和脂肪酸提供理论依据,并为鉴别海洋鱼油质量提供基础数据。结果表明:鱼油软胶囊中主要含有C14~C22脂肪酸,其中不饱和脂肪酸质量分数50.8%~85.1%,特别是具有重要生理作用的多不饱和脂肪酸,如C20:5(EPA,约占10.0%~35.1%)、C22:6(DHA,约占10.7%~20.5%);鱼油软胶囊中n-3不饱和脂肪酸质量分数约为22.5%~55.7%,n-6不饱和脂肪酸与n-3不饱和脂肪酸的比率约为0~0.7,EPA与DHA的比率约为0.8~1.9。 相似文献
14.
超临界CO2连续式萃取精馏鱼油中EPA和DHA的试验研究 总被引:4,自引:0,他引:4
研究了用超临界CO2萃取鱼油中EPA和DHA的连续式流程,探讨了鱼油与CO2流量比、压力、温度梯度以萃取效果的影响,并进一步探讨了萃取的工艺参数。 相似文献
15.
本文以宝石鱼为原料,利用气相色谱法来鉴定宝石鱼鱼油中的的脂肪酸组成,通过与标准脂肪酸色谱图比较共确定25种脂肪酸,其中以16:0、18:0、18:1n-9、18:2n-6、22:6n-3、20:4n-3、22:5n-3(EPA)和22:6n-3(DHA)。为主。 相似文献
16.
17.
Fatty acid profiles and fat contents of commercially important seawater and freshwater fish species of Turkey: A comparative study 总被引:2,自引:0,他引:2
The fat content and fatty acid compositions of edible muscle of commercially important seawater and freshwater fish species were investigated. The fatty acid compositions of seawater fish species were found to be 25.5–39.4% saturated (SFA), 13.2–29.0% monounsaturated (MUFAs) and 25.2–48.2% polyunsaturated acids (PUFAs), whereas the fatty acid compositions of freshwater fish from Lake Seyhan consisted of 28.0–34.6% saturated (SFA), 10.7–22.7% monounsaturated (MUFAs) and 23.2–43.7% polyunsaturated acids (PUFAs). The proportions of n3 PUFAs of seawater fish (ranging from 22.6 for waker to 44.2% for blue fish) were higher than those of n3 PUFAs of freshwater fish (ranging from 11.5% for North African catfish to 28.4% for zander). However, the levels of n6 PUFAs of seawater fish (ranging from 0.43% for blue fish to 14.4% for sea bass) were lower than those of n6 PUFAs of freshwater fish (ranging from 5.27% for kutum to 16.8% for tench). The results showed that fatty acid profiles of most freshwater fish are basically comparable to those of seawater fish as sources of PUFAs. 相似文献
18.
19.
The 3% chitosan solutions incorporating 10% fish oil (w/w chitosan, containing 91.2% EPA and DHA) with or without the addition of 0.8% vitamin E were prepared. Fresh lingcod (Ophiodon elongates) fillets were vacuum-impregnated in coating solution at 100 mm Hg for 10 min followed by atmospheric restoration for 15 min, dried, and then stored at 2 °C or −20 °C for 3-weeks and 3-months, respectively, for physicochemical and microbial quality evaluation. Chitosan–fish oil coating increased total lipid and omega-3 fatty acid contents of fish by about 3-fold, reduced TBARS values in both fresh and frozen samples, and also decreased drip loss of frozen samples by 14.1–27.6%. Chitosan coatings resulted in 0.37–1.19 and 0.27–1.55 log CFU/g reductions in total plate and psychrotrophic counts in cold stored and frozen stored samples, respectively. Chitosan–fish oil coatings may be used to extend shelf-life and fortify omega-3 fatty acid in lean fish. 相似文献
20.
以LiAlH_4为还原剂,试图降低富含高度不饱和脂肪酸乙酯(主要是5、8、11、14、17、——廿碳五烯酸乙酯,5、8、11、14、17、20——廿二碳六烯酸乙酯。分别简称为EPA乙酯,DHA乙酯)的鱼油酸乙酯的过氧化值。其中,以乙醚为溶剂,LiAlH_4的用量为3%,反应时间为60~90min,去过氧化值的效果显著,方法较简便。 相似文献