Perhaps you should try some spelling variations:
cua tre » cua te, cuu tre, cua triet
duc van » duc va, duc tan, duc manh
ky sang » ky nang, ky dang, ky tang
sang ma » tang ma, nang ma, sang tao
hieu ve » hieu van
hoc can » hoc dan, hoc cao, hoc cac
hieu va » lieu va, hieu qua
vi cua » vai cua, di cua
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, ma hoa

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: te sac ky sang ma hoi. ((hieu ve) OR (hieu va)) cac ((duc van) OR (hoc can)) hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky sang ma hoi. ((hieu ve) OR (hieu va)) cac ((duc van) or (hoc can)) hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: te sac ky sang ma hoi. ((hieu ve) OR (hieu va)) cac ((duc van) or (hoc can)) hanh vi cua tre*.