Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu quang » thieu quang, hieu quan, diep quang
trung hoc » trung quoc
hang cong » dang cong, hang nong, bang cong
hoc hang » hoc hanh, hoc bang, hoc tang
cong san » cong tac
toan cau » toan ban, toan tap, toan tai
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: ho ((hieu quang) OR (hieu qua)) - thanh trung hoc hang cong san ((toan cau) or (toan cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((hieu quang) OR (hieu qua)) - thanh trung hoc hang cong san ((toan cau) OR (toan cao)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu quang) OR (hieu qua)) - thanh trung hoc hang cong san ((toan cau) or (toan cao))".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu quang) OR (hieu qua)) - thanh trung hoc hang cong san ((toan cau) or (toan cao))*.