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
cap phan » cac phan, cao phan, cap han
cong sat » cong suat, cong san, cong hat
sat nhan » hat nhan, sat phan, ca nhan
nhan dau » phan dau, nhan dan, han 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 (cap phan)) cong sat nhan 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 (cap phan)) cong sat nhan dau.
• Adding a wildcard symbol may retrieve word variants: hoc ((thuyet mach) or (thuyet cac)) - thanh tung ((cap xay) or (cap phan)) cong sat nhan dau*.