Perhaps you should try some spelling variations:
thuong cong » thong cong, thuong con, thuong dong
hieu lang » chieu sang, hieu quang, nhieu tang
hoc hieu » hoc thieu, hoc hien, doc hieu
cong tan » cong tac, cong san, cong thanh
than cau » toan cau, than cap, thanh chau
phan cau » phan dau, phan cac, phan tu
cong va » dong va, cong tac, luong va
cong ha » cong hoa, dong ha, cong tac

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 ((cong va) OR (cong ha)) thuong cong tan ((than cau) or (phan cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - thanh ((cong va) OR (cong ha)) thuong cong tan ((than cau) OR (phan cau)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu lang - thanh ((cong va) OR (cong ha)) thuong cong tan ((than cau) or (phan cau))".
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - thanh ((cong va) OR (cong ha)) thuong cong tan ((than cau) or (phan cau))*.