Dalian is an important crude oil reserves and refining and chemical base of China and its crude oil demand is very big.

大连是国家重要的原油储备以及炼化基地，对进口原油的需求量较大。

youdao

The Yulin City locates in the Erdos basin, and it is important component of energy source and chemical base in the north of Shaanxi province.

榆林市位于鄂尔多斯盆地，是陕北能源重化工基地的重要组成部分。

youdao

Petroleum and the natural gas resources in Puyang City are rich, and Puyang City is the important petroleum and chemical base of Henan Province.

濮阳市石油、天然气资源丰富，是河南省重要的石油、化工基地。

youdao

So the access that a cell has to certain kinds of genes, or chemical modifications of DNA, not chemical modifications that change the base pairs, that would be a mutation.

因此细胞变化的途径应该是对某些基因,或者DNA进行化学修饰,不是更改碱基对,更改碱基对就是突变了

耶鲁公开课 - 生物医学工程探索课程节选

The men had volunteered for experiments at the government's chemical warfare research base at Porton Down in Wiltshire in 1953 and 1954.

BBC: NEWS | UK | MI6 payouts over secret LSD tests

Both have lost their economic base: Guben its chemical-fibre plant, Gubin its garrison.

ECONOMIST: The German-Polish border

The winners will have to do it accurately, making no more than one mistake per million base pairs (the chemical letters in which genomic information is encoded).

ECONOMIST: A new prize for the genomics of the elderly is now on offer