Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh luat, trinh han
hieu xanh » chieu xanh, hieu manh, hieu nganh
nang cong » nang song, dang cong, bang cong
doc hieu » toc thieu, hoc thieu, hoc hien
trinh va » trinh van, trinh vat, trinh ve
cong san » cong tac
tuan thu » toan thuc

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - hanh ((trinh va) OR (trinh quan)) nang cong san ((tuan thu) OR (van thu))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - hanh ((trinh va) or (trinh quan)) nang cong san ((tuan thu) OR (van thu))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh ((trinh va) or (trinh quan)) nang cong san ((tuan thu) OR (van thu))*.