Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
hanh ve » hanh vi, hanh va, hanh kem
duc ban » duc tan, duc van, dua ban
sach ky » sac ky, sach y, sach ty
va pham » van pham, va phat, va phap
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
anh ve » anh va, anh viet, thanh ve
o hai » co hai, so hai, o lai
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 ky nang ((x hoi) or (o hai)). hieu va pham duc ban ((anh ve) or (hanh ve)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((x hoi) OR (o hai)). hieu va pham duc ban ((anh ve) OR (hanh ve)) cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((x hoi) or (o hai)). hieu va pham duc ban ((anh ve) or (hanh ve)) cua tre*.