Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
dong thanh » truong thanh
hoc thieu » toc thieu, hoc hien
doc hieu » toc thieu, hoc hien
trinh va » trinh van, trinh vat, trinh ve
cong san » cong tac
van dau » van dao, phan dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc thieu) or (doc hieu)) xanh - canh trinh va nhung ((dong thanh) or (cong san)) van dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thieu) OR (doc hieu)) xanh - canh trinh va nhung ((dong thanh) OR (cong san)) van dau.
• Adding a wildcard symbol may retrieve word variants: ((hoc thieu) or (doc hieu)) xanh - canh trinh va nhung ((dong thanh) or (cong san)) van dau*.