Perhaps you should try some spelling variations:
thieu nien » thien nhien
hieu vien » hieu hien, hieu viec, hieu tieng
cua tre » cuu tre, cua triet, dua tren
bach tu » bach thu, cach tu, bac tu
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
ca dan » cac dan, ca dao
dan vi » doan vi, don vi, dan va
cua te » cua tu
tu ca » tu cac, tu cua, tu can
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang x hoi. ((hieu vien) or (thieu nien)) bach tu ca dan vi ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. ((hieu vien) OR (thieu nien)) bach tu ca dan vi ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. ((hieu vien) or (thieu nien)) bach tu ca dan vi ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. ((hieu vien) or (thieu nien)) bach tu ca dan vi ((cua tre) OR (cua te))*.