Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tu sach » thu sach, su sach, te sach
tai cua » thai cua, tai cuc, tri cua
han tai » hang tai, nhan tai, van tai
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
cao hoi » cau hoi, co hoi, cao hoc
cua tre » cua te, cuu tre, cua triet
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: ((tu sach) or (toc sach)) ky nang cao hoi. hieu ve cham ((tuc va) or (thuc vat)) han tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) ky nang cao hoi. hieu ve cham ((tuc va) OR (thuc vat)) han tai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky nang cao hoi. hieu ve cham ((tuc va) or (thuc vat)) han tai cua tre*.