Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, hieu manh
trinh xac » trinh xay, trinh cac, trinh xuan
hoc hieu » hoc thieu, hoc hien, doc hieu
tinh xay » trinh xay, tinh tay, tinh xach
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
hang dau » hang va, hang tai

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu nganh - canh ((tinh xay) OR (trinh xac)) dung ((cong dan) or (cong san)) hang dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu nganh - canh ((tinh xay) OR (trinh xac)) dung ((cong dan) OR (cong san)) hang dau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu nganh - canh ((tinh xay) OR (trinh xac)) dung ((cong dan) or (cong san)) hang dau".
• Adding a wildcard symbol may retrieve word variants: hoc hieu nganh - canh ((tinh xay) OR (trinh xac)) dung ((cong dan) or (cong san)) hang dau*.