Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
truong va » truong dai, truong cao, truong dao
dang cong » dung cong
hoc hieu » hoc thieu, hoc hien, doc hieu
trung va » trang va, trung ha, trung tam
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan cau » 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: hoc hieu lang - thanh ((trung va) or (truong va)) dang cong san toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - thanh ((trung va) OR (truong va)) dang cong san toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - thanh ((trung va) or (truong va)) dang cong san toan cau*.