Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
ban thanh » ban hanh, ban hang
su sach » so sach, vu sach
vai cua » dai cua, hai cua, lai cua
mua ban » cua ban, qua ban
nam mua » nam cua, nam qua, nam xua
hieu va » lieu va
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu van
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa

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 y nang ma hoi. ((hieu ve) or (((hieu va) OR (hieu qua)))) nam mua ban thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ma hoi. ((hieu ve) OR (((hieu va) OR (hieu qua)))) nam mua ban thanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang ma hoi. ((hieu ve) or (((hieu va) OR (hieu qua)))) nam mua ban thanh vai cua tre*".