Perhaps you should try some spelling variations:
thuyet mach » thuyet xac, thuyet cac, thuyet anh
hoc thuyet » hoc chuyen
thanh tung » thanh cong
cong thanh » dong thanh, cong trinh, truong thanh
khang dau » hang dau, phan dau, xang dau
cap phan » cac phan, cao phan, cau phan
cong tan » cong tac, cong san, cong ty
cap han » cap can, cap hay, cap van

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 - thanh tung ((cap han) or (cap phan)) ((cong tan) OR (cong thanh)) khang dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thuyet mach - thanh tung ((cap han) OR (cap phan)) ((cong tan) OR (cong thanh)) khang dau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thuyet mach - thanh tung ((cap han) or (cap phan)) ((cong tan) OR (cong thanh)) khang dau".
• Adding a wildcard symbol may retrieve word variants: hoc thuyet mach - thanh tung ((cap han) or (cap phan)) ((cong tan) OR (cong thanh)) khang dau*.