Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
trang va » tran van
hanh dai » hanh tai, hanh dao, vanh dai
sach ty » sach y, sach tu, sach thu
van cau » van dau, van hau, van chat
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
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 ty) or (sac ky)) nang x hoi. hieu van cau ((trang va) or (hang va)) hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sac ky)) nang x hoi. hieu van cau ((trang va) OR (hang va)) hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sac ky)) nang x hoi. hieu van cau ((trang va) or (hang va)) hanh dai cua tre*.