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
tong cong » trong cong, cong cong, dang cong
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
huy van » thuy van, quy van, huy can
duy van » duy vat, dung 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 ((tong cong) or (dung cong)) ((huy van) OR (duy van)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh tranh cua ((tong cong) OR (dung cong)) ((huy van) OR (duy van)) ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu lang - hanh tranh cua ((tong cong) or (dung cong)) ((huy van) OR (duy van)) ban".
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - hanh tranh cua ((tong cong) or (dung cong)) ((huy van) OR (duy van)) ban*.