Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
nhung cong » dung cong, thong cong, nhung don
hieu manh » chieu xanh, hieu nganh, dieu hanh
hang cong » dang cong, hang nong, bang cong
hoc hieu » hoc thieu, hoc hien, doc hieu
trinh va » trinh van, trinh vat, trinh ve
toan tap » toan ban
toan cao » toan ban

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: hoc hieu manh - hanh trinh va ((nhung cong) OR (hang cong)) tinh ((toan tap) OR (toan cao))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu manh - hanh trinh va ((nhung cong) OR (hang cong)) tinh ((toan tap) or (toan cao))~".
• Adding a wildcard symbol may retrieve word variants: hoc hieu manh - hanh trinh va ((nhung cong) OR (hang cong)) tinh ((toan tap) or (toan cao))*.