Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien cac » vien bach, vien dai, vien da
hang tai » dung tai
van nang » van quang, van ban, van dong
cac duc » cac du, cao duc, cac dac
duc ban » duc tan, duc van, dua ban
tu sach » thu sach, su sach, te sach
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, voi nang
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 ((v nang) OR (van nang)) x hoi. hieu vien cac duc ban ((hang tai) or (hang va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((v nang) OR (van nang)) x hoi. hieu vien cac duc ban ((hang tai) OR (hang va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((v nang) OR (van nang)) x hoi. hieu vien cac duc ban ((hang tai) or (hang va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((v nang) OR (van nang)) x hoi. hieu vien cac duc ban ((hang tai) or (hang va)) cua tre*.