Classification
660 - Chemical engineering
6
665 - Industrial oils, fats, waxes & gases
5
661 - Industrial chemicals
4
662 - Explosives, fuels & related products
4
541 - Physical chemistry
2
553 - Economic geology
2
628 - Sanitary & municipal engineering
2
629 - Other branches of engineering
2
546 - Inorganic chemistry
1
574 - [Unassigned]
1
621 - Applied physics
1
622 - Mining & related operations
1
666 - Ceramic & allied technologies
1
668 - Technology of other organic products
1