Perhaps you should try some spelling variations:
cua tre » cua te, cuu tre, cua triet
nang du » nang tu, nang luc, nang doc
hieu ve » hieu va, hieu van
van hoi » van hoa, van hoe, van loi
van hoc » van hoa
ky lang » ky nang, ky dang, ky tang
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
bac va » bac ha, bao va, tac va
du cua » duy cua, dau cua, dum cua
tu sac » tu sach, tu cac, tu san

You may be able to get more results by adjusting your search query.

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