Perhaps you should try some spelling variations:
thanh trung » thanh tung
trung thac » trung thuc, trung thanh, trang thach
thac quang » tac quang, thai quang, than quang
hieu lang » chieu sang, hieu quang, nhieu tang
doi hieu » doi chieu, doc hieu, doi hien
duong va » duong van, dung va, luong va
dang van » hoang van, hang va
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 hieu lang - thanh trung thac quang ((duong va) or (dang van)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi hieu lang - thanh trung thac quang ((duong va) OR (dang van)) toan cau.
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - thanh trung thac quang ((duong va) or (dang van)) toan cau*.