Perhaps you should try some spelling variations:
nhung huong » nhung phuong, nhung tuong, nhung cong
hieu xanh » chieu xanh, hieu manh, hieu nganh
trinh vat » trinh van, trinh luat, sinh vat
doc hieu » toc thieu, hoc thieu, hoc hien
trinh va » trinh van, trinh ve, trinh vi
than cap » khan cap, thanh lap, thanh cac
toan cao » toan ban, toan tap

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 vat)) nhung huong dan ((than cap) OR (toan cao))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - hanh ((trinh va) OR (trinh vat)) nhung huong dan ((than cap) or (toan cao))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh ((trinh va) OR (trinh vat)) nhung huong dan ((than cap) or (toan cao))*.