Perhaps you should try some spelling variations:
thuyet mach » thuyet xac, thuyet anh
thuyet cac » thuyet xac, thuyet va, thuyet bai
thanh tung » thanh cong
cac phan » cac nhan, cao phan, cap phan
cong sat » cong suat, cong san, cong hat
sat phan » sat nhan, vat phan, xuat phan
phan dau » phan tu, hang dau
cap xay » cau xay

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thuyet mach) or (thuyet cac)) - thanh tung ((cap xay) or (cac phan)) cong sat phan dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thuyet mach) OR (thuyet cac)) - thanh tung ((cap xay) OR (cac phan)) cong sat phan dau.
• Adding a wildcard symbol may retrieve word variants: hoc ((thuyet mach) or (thuyet cac)) - thanh tung ((cap xay) or (cac phan)) cong sat phan dau*.