Perhaps you should try some spelling variations:
luoc can » luc canh, hoc can, luoc dai
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
duc van » duc tan, duc manh, duc phan
cua tre » cua te, cuu tre, cua triet
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
vi cua » vai cua, di cua

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 cao hoi. hieu ve cac ((((duc van) or (duc va))) or (luoc can)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky nang cao hoi. hieu ve cac ((((duc van) OR (duc va))) OR (luoc can)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: te sac ky nang cao hoi. hieu ve cac ((((duc van) or (duc va))) or (luoc can)) hanh vi cua tre*.