早期的橡胶是取自橡胶树、橡胶草等植物的胶乳，加工后制成的具有弹性、绝缘性、不透水和空气的材料。高弹性的高分子化合物。分为天然橡胶与合成橡胶二种。天然橡胶是从橡胶树、橡胶草等植物中提取胶质后加工制成；合成橡胶则由各种单体经聚合反应而得。橡胶制品广泛应用于工业或生活各方面。
This is the epic, untold story of how same-sex marriage became law of the land. Documenting one of t...
An investigative expose of the inner workings inside the commercial pet food industry, which has went largely unchallenged until now.
A documentary series that explores the furthest reaches of the internet and the people who frequent ...
骑士队完成了几乎不可能的1-3逆转，将总冠军带回克利夫兰。让我们跟随勒布朗-詹姆斯和整支球队回顾历史性的2016赛季，你将看到对球员的独家采访、幕后故事和官方Recap。这就是2015-16年克利夫兰...
