Perhaps you should try some spelling variations:
thiet tach » chiet tach, thien hach, thuat tach
hoc thiet » hoc thieu, hoc thuyet, hoc hien
hanh tang » hanh trang, anh tang, hanh mang
cong van » cong vang, song van, cong tan
cong san » cong tac
tang va » trang va, tang van, thang va
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 - hanh tang va nang ((cong van) OR (cong san)) thanh san~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thiet tach - hanh tang va nang ((cong van) OR (cong san)) thanh san".
• Adding a wildcard symbol may retrieve word variants: hoc thiet tach - hanh tang va nang ((cong van) OR (cong san)) thanh san*.