Perhaps you should try some spelling variations:
nang mai » nang ma, nang tai, lang mai
hanh vai » hanh vi, hanh va, hanh tai
luoc can » luc canh, hoc can, luoc dai
cua tre » cua te, cuu tre, cua triet
duc van » duc va, duc tan, duc manh
vai cua » dai cua, hai cua, lai cua
hieu va » lieu va, hieu qua
hieu ve » hieu van
mai hoi » mai khoi, dai hoi, lai hoi
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.

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky nang mai hoi. ((hieu ve) OR (hieu va)) cac ((duc van) or (luoc can)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky nang mai hoi. ((hieu ve) OR (hieu va)) cac ((duc van) OR (luoc can)) hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky nang mai hoi. ((hieu ve) OR (hieu va)) cac ((duc van) or (luoc can)) hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sac ky nang mai hoi. ((hieu ve) OR (hieu va)) cac ((duc van) or (luoc can)) hanh vai cua tre*.