Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
hieu quang » thieu quang, hieu qua, diep quang
hieu quan » hieu qua, lieu quan, thien quan
tranh cua » doanh cua, manh cua
cuong tap » luong tap, cong tac, luong tai
cong tap » cong tac, cong tan, tong tap
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((hieu quang) OR (hieu quan)) - hanh tranh cua cong ((cong tap) or (cuong tap)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu quang) OR (hieu quan)) - hanh tranh cua cong ((cong tap) OR (cuong tap)) toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((hieu quang) OR (hieu quan)) - hanh tranh cua cong ((cong tap) or (cuong tap)) toan cao".
• Adding a wildcard symbol may retrieve word variants: theo ((hieu quang) OR (hieu quan)) - hanh tranh cua cong ((cong tap) or (cuong tap)) toan cao*.