This is Scientific Americans 60-Second Science. Im Cynthia Graber. This will just take a minute. Saliva contains many useful components: lubricants, enzymes for breaking down food and now compounds that can reveal a persons age. Thats according to a

发表于:2018-12-24 / 阅读(64) / 评论(0) 分类 Scientific American(六)月

AGRICULTURE REPORT - Restrictions on Methyl Bromide By Mario Ritter Broadcast: Tuesday, March 16, 2004 This is Steve Ember with the VOA Special English Agriculture Report. Graphic Image Some chemicals

发表于:2019-01-06 / 阅读(90) / 评论(0) 分类 农业与发展

Science and Technology Epigenetics and stress Baby blues 科技 外因遗传与压力 新生儿蓝调曲 A mother's stress while she is pregnant can have a long-lasting effect on her children's genes 母亲孕期压力过大会对孩子的基因造成长

发表于:2019-01-26 / 阅读(58) / 评论(0) 分类 经济学人科技系列

By counting back through these layers and measuring the amount of lead in each, he could work out global lead concentrations at any time for hundreds, or even thousands, of years. The notion became the foundation of ice core studies, on which much mo

发表于:2019-02-17 / 阅读(60) / 评论(0) 分类 万物简史

If you were going to a restaurant and wanted a healthier option, 如果你去饭店,你想吃得健康一点, which would you choose, grilled or fried chicken? 你会选择哪种食品呢,烤鸡还是炸鸡? Now most people would answer grill

发表于:2019-02-21 / 阅读(68) / 评论(0) 分类 TED演讲教育篇

日常生活中,意外伤害很难避免。如果我们不及时救治或者操作不当的话,很可能会对自身或者他人的身体造成伤害,所以,掌握一些急救常识非常必要。下面我们来看一段关于学习急救的对

发表于:2019-02-26 / 阅读(76) / 评论(0) 分类 英语口语