Perhaps you should try some spelling variations:
thong cong » tong cong, thong thong, phong chong
hanh tranh » hanh trinh, hanh trang, lanh tranh
hieu lang » chieu sang, hieu quang, nhieu tang
tai nhanh » tai thanh, thai thanh, tai chinh
nhanh bac » nhanh ha, nhanh va
hoc hieu » hoc thieu, hoc hien, doc hieu

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) OR (canh tranh)) cua ((thong cong) or (trong cong)) tai nhanh bac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - ((hanh tranh) OR (canh tranh)) cua ((thong cong) OR (trong cong)) tai nhanh bac.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu lang - ((hanh tranh) OR (canh tranh)) cua ((thong cong) or (trong cong)) tai nhanh bac".
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - ((hanh tranh) OR (canh tranh)) cua ((thong cong) or (trong cong)) tai nhanh bac*.