Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh tai » thanh tai, hang tai, han tai
hieu van » hieu va, thien van, lieu va
tai cua » thai cua, tai cuc, tri cua
van cam » van nam, van lam, van cau
ty dang » ky dang, ty hang, ty dong
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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 ((ty dang) or (ty xang)) ma hoi. hieu van cam ((xuc va) or (tuc va)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty dang) OR (ty xang)) ma hoi. hieu van cam ((xuc va) OR (tuc va)) hanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty dang) or (ty xang)) ma hoi. hieu van cam ((xuc va) or (tuc va)) hanh tai cua tre*.