Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
bach tu » bach thu, cach tu, bac tu
cua dan » cua dang, cua ban, ca dan
cua tre » cua te, cuu tre, cua triet
tu cua » hu cua, vu cua
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua
x hoi » o hoi, x ho
5 hoi » o hoi

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) or (5 hoi))) or (xa hoi)). hieu vien bach tu cua dan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((((x hoi) OR (5 hoi))) OR (xa hoi)). hieu vien bach tu cua dan vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((((x hoi) or (5 hoi))) or (xa hoi)). hieu vien bach tu cua dan vi cua tre*.