Perhaps you should try some spelling variations:
khai sang » kha nang, nha sang, thai bang
dung cong » dung trong
doi khai » doi khi, toi khai, doi khang
trung va » truong va, trang va, trung tam
trung ha » trung hoc, trung tam, trung cap
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: doi khai sang - thanh ((trung va) or (trung ha)) dung cong san toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi khai sang - thanh ((trung va) OR (trung ha)) dung cong san toan cau.
• Adding a wildcard symbol may retrieve word variants: doi khai sang - thanh ((trung va) or (trung ha)) dung cong san toan cau*.