Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
hanh di » hanh vi, hanh de, hang di
duc van » duc va, duc tan, duc manh
hieu va » lieu va, hieu qua
hieu ve » hieu van
tang ma » mang may, tang van
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
sai ky » sac ky
di cua » dai cua, doi cua, de cua

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: thu ((sach thu) OR (sai ky)) tang ma hoi. ((hieu ve) OR (hieu va)) giao duc van hanh di cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach thu) or (sai ky)) tang ma hoi. ((hieu ve) OR (hieu va)) giao duc van hanh di cua tre~".
• Adding a wildcard symbol may retrieve word variants: thu ((sach thu) or (sai ky)) tang ma hoi. ((hieu ve) OR (hieu va)) giao duc van hanh di cua tre*.