Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trang vat » trang vai, tang vat, trang mat
dung cong » dung trong
cong manh » cong danh, duong manh, cong thanh
hoi hieu » hoi phieu, hoi tieu, moi hieu
trang va » tran van, hang va
toan cau » toan cao, toan tap, toan tai
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoi hieu quang - hanh ((trang vat) or (trang va)) dung cong manh ((toan cau) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoi hieu quang - hanh ((trang vat) OR (trang va)) dung cong manh ((toan cau) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: hoi hieu quang - hanh ((trang vat) or (trang va)) dung cong manh ((toan cau) or (toan ban))*.