Perhaps you should try some spelling variations:
cong thanh » dong thanh, cong trinh, cong tan
hanh tranh » canh tranh, hanh trinh, hanh trang
hien xanh » hien hanh, hien nhanh, chieu xanh
cong hoan » cong hoa, dong hoa, cong san
tranh va » tranh van, trang va, trinh va
ban banh » ban hanh, ban anh, ban danh
va dung » van dung, va duong, vat dung
ban ban » van ban, can ban, ban dan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien xanh - hanh tranh va dung ((cong hoan) or (cong thanh)) ((ban ban) or (ban banh))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - hanh tranh va dung ((cong hoan) OR (cong thanh)) ((ban ban) OR (ban banh)).
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - hanh tranh va dung ((cong hoan) or (cong thanh)) ((ban ban) or (ban banh))*.