Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
hang tai » hang va, dung tai
cua tre » cua te, cuu tre, cua triet
duc van » duc va, duc tan, duc manh
vai cua » dai cua, hai cua, lai cua
hoc can » hoc dan, hoc cao, hoc cac
hieu va » lieu va, hieu qua
sac ky » cac ky, sai ky
te sac » te sach, te cac, te san

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