Perhaps you should try some spelling variations:
cong thanh » dong thanh, cong trinh, truong thanh
hieu lang » chieu sang, hieu quang, nhieu tang
doi hieu » doi chieu, doc hieu, doi hien
trang va » hang va
tran van » luan van
cong tan » cong tac, cong san, cong ty
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 ((trang va) or (tran van)) thuong ((cong tan) OR (cong thanh)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi hieu lang - thanh ((trang va) OR (tran van)) thuong ((cong tan) OR (cong thanh)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi hieu lang - thanh ((trang va) or (tran van)) thuong ((cong tan) OR (cong thanh)) toan cau".
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - thanh ((trang va) or (tran van)) thuong ((cong tan) OR (cong thanh)) toan cau*.