Perhaps you should try some spelling variations:
nhanh tinh » nhanh thanh, hanh trinh, nhan sinh
hieu manh » chieu xanh, hieu nganh, dieu hanh
hanh tinh » hanh trinh, thanh tinh, canh tinh
chat dung » chan dung, chat luong, chat quang
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
cong van » cong vang, cong san, song van
phan dau » phan tu
hang dau » hang va, hang tai

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 manh - ((hanh tinh) OR (nhanh tinh)) chat dung cong van ((phan dau) OR (hang dau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu manh - ((hanh tinh) or (nhanh tinh)) chat dung cong van ((phan dau) OR (hang dau))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu manh - ((hanh tinh) or (nhanh tinh)) chat dung cong van ((phan dau) OR (hang dau))*.