Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hoc sach » hoc sinh, hoc cac, hoc anh
cau thuc » cau truc, cuu thuc, can thuc
lap chau » lai chau, a chau, ha chau
chau tre » chay tren, chau tho, cho tre
su sach » so sach, vu sach
van cau » van dau, van hau, van chat
thuc va » thuc vat, thuc dan, thuc day
dan lap » phan lap, dan luan
y nang » ky nang, ly nang, v nang
va dan » ca dan, va dao, va dau
x hoi » xa hoi, o hoi, 5 hoi

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (hoc sach)) y nang ((x hoi) OR (x ho)). hieu van cau thuc va dan lap chau tre~.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (hoc sach)) y nang ((x hoi) or (x ho)). hieu van cau thuc va dan lap chau tre*.