Perhaps you should try some spelling variations:
thieu nien » thien nhien
hieu vien » hieu hien, hieu viec, hieu tieng
tu sach » thu sach, su sach, tu cach
can dan » canh dan, cac dan, can ban
bach tu » bach thu, cach tu, bac tu
te sach » toc sach
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
tu can » tu ban, tu cac, thu canh
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua
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) or (te sach)) y nang x hoi. ((hieu vien) or (thieu nien)) bach tu can dan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) y nang x hoi. ((hieu vien) OR (thieu nien)) bach tu can dan vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) y nang x hoi. ((hieu vien) or (thieu nien)) bach tu can dan vi cua tre*.