Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
hieu lang » chieu sang, hieu quang, nhieu tang
tranh cua » doanh cua, manh cua
dang cong » dung cong
cong cong » cong dong, trong cong, dung cong
hoc hieu » hoc thieu, hoc hien, doc hieu
huy van » thuy van, duy van, quy 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 hieu lang - hanh tranh cua ((dang cong) or (cong cong)) huy van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh tranh cua ((dang cong) OR (cong cong)) huy van ban.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - hanh tranh cua ((dang cong) or (cong cong)) huy van ban*.