Perhaps you should try some spelling variations:
luoc can » luc canh, hoc can, luoc dai
cua tre » cua te, cuu tre, cua triet
hanh di » hanh vi, hanh de, hang di
duc van » duc va, duc tan, duc manh
hieu ve » hieu va, hieu van
tao hoi » tao khoi, tao boi, thao hoc
tay hoi » tay ho, tay thai
ky sang » ky nang, ky dang, ky tang
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
di cua » dai cua, doi cua, de cua
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 sang ((tao hoi) OR (tay hoi)). hieu ve cac ((duc van) or (luoc can)) hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky sang ((tao hoi) OR (tay hoi)). hieu ve cac ((duc van) OR (luoc can)) hanh di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky sang ((tao hoi) OR (tay hoi)). hieu ve cac ((duc van) or (luoc can)) hanh di cua tre".
• Adding a wildcard symbol may retrieve word variants: te sac ky sang ((tao hoi) OR (tay hoi)). hieu ve cac ((duc van) or (luoc can)) hanh di cua tre*.