Perhaps you should try some spelling variations:
thiet tach » chiet tach, thuat tach
thien hach » thien thanh, hien hanh
canh trinh » canh tranh, hanh trinh, canh tinh
trinh van » trinh han, trinh quan, trinh toan
vuong tan » vuong tuan, vuong tat, vuong van
duong tan » duong tuan, duong van, duong tai
van hung » van dung, manh hung, van duong
toan cau » toan cao, toan ban, toan tap

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) OR (thien hach)) - canh trinh van hung ((vuong tan) or (duong tan)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thiet tach) OR (thien hach)) - canh trinh van hung ((vuong tan) OR (duong tan)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thiet tach) OR (thien hach)) - canh trinh van hung ((vuong tan) or (duong tan)) toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thiet tach) OR (thien hach)) - canh trinh van hung ((vuong tan) or (duong tan)) toan cau*.