全部文献期刊学位论文会议报纸专利标准年鉴图书|学者科研项目
中外文文献  中文文献  外文文献
作者:李伟 , 张宝贵
来源:[J].南开大学学报(自然科学版), 2004, (03), pp.61-65+72CNKI
摘要:研究了在相同条件下制备的NiB、NiP和NiPB非晶态合金的物性与催化性能,结果表明,NiB非晶态合金具有较高的催化活性,但热稳定性相对较差;NiP非晶态合金热稳定性较高,但催化活性较低;NiPB非晶态合金既具有高活性又...
被引频次:9下载频次:175
作者:... 何亚维 , 黄泉秀 , 李伟
来源:[J].中国野生植物资源, 1994, (03), pp.15-17CNKI
摘要:本文首次应用以桔梗皂甙D为标准品、香草醛-硫酸系统为显色剂的比色法,在波长480nm处测定了不同采收期桔梗的总皂甙含量,结果表明:采集桔梗的最佳时期为其营养生长盛期和末期。本法用于...
被引频次:13下载频次:96
作者:布赫 , 何五星 , 李伟
来源:[J].财经问题研究, 1994, (05), pp.56-60CNKI
摘要:对民族地区沿边开放战略的构想布赫,何五星,李伟一个国家或地区的经济能否兴旺发达,除了自身基本条件外,很大程度上取决于能否实行对外开放政策,同时,也离不开制定科学的发展战略。我国是一...
被引频次:3下载频次:73
作者:李伟 , 李舒
来源:[J].Advances in Clinical Medicine, 2018, Vol.08 (02), pp.160-164汉斯出版社
摘要:microRNAs (miRNAs) are endogenous approximately 22 nucleotide non-coding RNAs that post-transcriptionally regulate gene expression via binding to 3’ untranslated regions. Autophagy is a highly conserved pathway for the degradation of damaged organelles and other macromolecul...
作者:李伟
来源:[J].Advances in Education, 2018, Vol.08 (05), pp.487-491汉斯出版社
摘要:Based on the course of college physics, this paper makes an empirical study on the structure and stability of cooperative learning groups. Cooperative and effective group structure and group leader selection can promote the effective learning effect of group cooperation. Through ...
作者:谢华 , 李伟 , 张世采
来源:[J].口腔正畸学杂志, 1994, (01), pp.27-29CNKI
摘要:本文利用文献计量学的方法,对美国IndexMedicus(简称IM)在1982年至1991年间所收录的有关口腔正畸学的七个主题词下全部文献的年代分布、语种、期刊公布、第一作者、中文...
被引频次:2下载频次:39
作者:... 马春慧 , 李伟 , 刘守新
来源:[J].Botanical Research, 2018, Vol.07 (01), pp.21-28汉斯出版社
摘要:In this study, the total flavonoids was extracted from Phyllostachys pubescens leaves by homoge-nate-assisted negative-pressure cavitation method. The volume fraction of alcohol, homogenate time, the solid to liquid ratio, the air velocity, the cavitation equipment shape and...
作者:李伟 , 刘守新
来源:[J].Botanical Research, 2018, Vol.07 (01), pp.37-44汉斯出版社
摘要:In this study, Rattan (palm cane) was extracted by homogenate-assisted extraction as raw material. A research has been conducted about ethanol volume fraction, feed liquid ratio, homogenate time, cavitation time, cavitation velocity, and the instrument shape in order to find...
作者:李伟 , 张温典
来源:[J].Hans Journal of Agricultural Sciences, 2018, Vol.08 (08), pp.942-947汉斯出版社
摘要:Protein, starch, crude fat, ash and crude fiber content of 32 foxtail millet varieties were measured and compared. These varieties were planted in the same field in Chengde. The results indicated that the content of protein, starch, crude fat, ash and crude fiber were in the...
作者:胡亮 , 李伟 , 谢勇
来源:[J].Computer Science and Application, 2018, Vol.08 (10), pp.1527-1534汉斯出版社
摘要:Tax assessment is an important and complicated task. Under the situation that there isn’t a very effective warning model for tax assessment at present, this paper points out a way of using recurrent neural network (RNN) to establish warning model of tax assessment, and selec...

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