Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
bang cong » dang cong, bang song, hang cong
doc hieu » toc thieu, hoc thieu, hoc hien
theo chu » theo chieu, cho chu, chao chu
tranh va » tranh van, trang va, trinh va
cong tan » cong tac, cong san, cong thanh
va bang » va nang, va lang, va ban
tan van » tran van, tang van, luan van

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc hieu) or (theo chu)) xanh - hanh tranh va bang cong tan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (theo chu)) xanh - hanh tranh va bang cong tan van ban.
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (theo chu)) xanh - hanh tranh va bang cong tan van ban*.