Perhaps you should try some spelling variations:
nang cai » nang cao, nang tai, nang cap
hanh vai » hanh vi, hanh va, hanh tai
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
cai hoi » cau hoi, dai hoi, cai hoa
hieu ve » hieu va, hieu van
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
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: so sach ky nang cai hoi. hieu ve cam ((duc va) or (tuc va)) hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang cai hoi. hieu ve cam ((duc va) OR (tuc va)) hanh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach ky nang cai hoi. hieu ve cam ((duc va) or (tuc va)) hanh vai cua tre*.