Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
hieu ve » hieu van
hieu va » lieu va, hieu qua
xuc ban » cuc ban, quoc ban, xuat ban
duc ban » duc tan, duc van, dua ban
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky tang xa hoi. ((hieu ve) OR (hieu va)) cam ((xuc ban) or (duc ban)) thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang xa hoi. ((hieu ve) OR (hieu va)) cam ((xuc ban) OR (duc ban)) thanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky tang xa hoi. ((hieu ve) OR (hieu va)) cam ((xuc ban) or (duc ban)) thanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky tang xa hoi. ((hieu ve) OR (hieu va)) cam ((xuc ban) or (duc ban)) thanh dai cua tre*.