Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach, thuat tach
thanh tung » thanh cong
hoc thiet » hoc thieu, hoc thuyet, hoc hien
nang cong » nang song, dang cong, bang cong
cong sang » cong san, cong lang, cong vang
sang than » cang thang, dang thanh, sang tao
than cau » toan cau, phan cau, than cap
va nang » van nang, da nang, cam nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thiet tach - ((thanh trung) or (thanh tung)) va nang cong sang than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thiet tach - ((thanh trung) OR (thanh tung)) va nang cong sang than cau*.