Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
hanh tai » thanh tai, hang tai, han tai
sach thu » sach thieu, sach tham, cach thuc
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa
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: toc ((sach thue) or (sach thu)) nang x hoi. hieu va cac ((luc va) or (tuc va)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach thue) OR (sach thu)) nang x hoi. hieu va cac ((luc va) OR (tuc va)) hanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc ((sach thue) or (sach thu)) nang x hoi. hieu va cac ((luc va) or (tuc va)) hanh tai cua tre*.