全文获取类型
收费全文 | 295篇 |
免费 | 13篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 12篇 |
综合类 | 16篇 |
化学工业 | 44篇 |
金属工艺 | 13篇 |
机械仪表 | 11篇 |
建筑科学 | 3篇 |
矿业工程 | 3篇 |
能源动力 | 5篇 |
轻工业 | 144篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
武器工业 | 18篇 |
无线电 | 13篇 |
一般工业技术 | 7篇 |
冶金工业 | 3篇 |
原子能技术 | 1篇 |
自动化技术 | 14篇 |
出版年
2023年 | 1篇 |
2022年 | 15篇 |
2021年 | 15篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 12篇 |
2012年 | 27篇 |
2011年 | 24篇 |
2010年 | 16篇 |
2009年 | 11篇 |
2008年 | 11篇 |
2007年 | 22篇 |
2006年 | 16篇 |
2005年 | 21篇 |
2004年 | 18篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1989年 | 3篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有314条查询结果,搜索用时 0 毫秒
311.
采用碘吸收滴定法测定了几种食品中二氧化硫的残留量及比较了不同预处理方法对二氧化硫含量的影响。以白木耳,笋衣为原料,采用GB/T 5009.34的改进方法测定食品中二氧化硫残留量,比较了25℃自来水浸泡、煮沸法、小苏打浸泡法,60℃热水浸泡法及醋酸浸泡法对样品中二氧化硫含量的影响。五种方法中除醋酸浸泡法减少样品中二氧化硫的效果最差,其余4种方法均能有效地降低食品中二氧化硫的残留量,其中沸水煮沸20min后能完全驱除二氧化硫,该方法简便、实用且易于操作;其次是60℃水浴3h,然后是0.5%小苏打溶液浸泡5 6h和25℃自来水浸泡处理5 6h。 相似文献
312.
We investigated the effects of nitrogen supply and shoot trimming on mature, field-grown Pinot Noir ( Vitis vinifera L.) vines. Ammonium nitrate (0, 30, 60, 90 kg N/ha) was applied at the beginning of flowering. Shoots were topped either once (at fruit set), or twice, (at fruit set and during the lag-phase of berry growth). Neither treatment affected grape berry and skin weights, yield and grape sugar, but high rates of nitrogen increased malic acid and reduced skin phenols, flavonols and anthocyanins. Malvidin-3-glucoside was the most abundant anthocyanin in skins and wine. It accounted for 75% of the total anthocyanins at the beginning of fermentation and its relative proportion increased to 95% in the finished wine.
Increases in anthocyanin concentration at the beginning of fermentation and before malolactic fermentation, were followed by declines during the later stages of alcoholic and malolactic fermentation. High nitrogen supply decreased anthocyanins in the juice and wine, increased pH and increased the percentage of malvidin-3-glucoside. Repeated shoot topping gave lower wine total phenols and anthocyanins and thus enhanced the nitrogen effect. Wine susceptibility to oxidation increased with higher pH and lower anthocyanin content. The best treatment combination for fruit and wine quality, in terms of colour and oxidative stability, was low nitrogen/single topping and the worst combination was high nitrogen/repeated topping. These results suggest that a combination of high rates of nitrogen fertiliser and repeated shoot trimming can decrease potential fruit and wine quality. 相似文献
Increases in anthocyanin concentration at the beginning of fermentation and before malolactic fermentation, were followed by declines during the later stages of alcoholic and malolactic fermentation. High nitrogen supply decreased anthocyanins in the juice and wine, increased pH and increased the percentage of malvidin-3-glucoside. Repeated shoot topping gave lower wine total phenols and anthocyanins and thus enhanced the nitrogen effect. Wine susceptibility to oxidation increased with higher pH and lower anthocyanin content. The best treatment combination for fruit and wine quality, in terms of colour and oxidative stability, was low nitrogen/single topping and the worst combination was high nitrogen/repeated topping. These results suggest that a combination of high rates of nitrogen fertiliser and repeated shoot trimming can decrease potential fruit and wine quality. 相似文献
313.
本文研究了超微粉碎技术对竹笋壳粉的基本组成、物理性质以及对亚硝酸根和胆固醇的吸附能力的影响。结果显示:超微粉碎处理后竹笋壳粉的水分、灰分、蛋白质和膳食纤维含量保持稳定的同时其平均粒径由383.90 μm降至12.69 μm。另外粉体亮度显著提升(p<0.05),红色度和黄色度均显著降低(p<0.05)。竹笋壳超微粉的持水性和持油性无显著变化,溶胀性显著降低(由7.48 mL/g降至5.50 mL/g)(p<0.05)。竹笋壳超微粉对亚硝酸根离子和胆固醇吸附量分别为558.26 μg/g(pH2.0)、346.19 μg/g(pH7.0),吸附能力分别提升了24.6%和9.1%(p<0.05)。傅立叶红外光谱显示超微粉碎对竹笋壳粉中羟基,糖类亚甲基以及木质素中芳香族化合物没有影响。同时扫描电镜观察发现超微粉碎造成粉体颗粒表面呈蜂窝状。故超微粉碎处理能够较好的维持竹笋壳粉的基本组成成分,并改善其理化性质。 相似文献
314.