Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
su sach » so sach, vu sach
cam duc » cam xuc, cao duc, pham duc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va
ty nang » ty xang, ty hang, ly nang
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua

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 ((ty nang) OR (ky nang)) ma hoi. ((hieu ve) or (hieu van)) cam duc va thanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ty nang) OR (ky nang)) ma hoi. ((hieu ve) OR (hieu van)) cam duc va thanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ty nang) OR (ky nang)) ma hoi. ((hieu ve) or (hieu van)) cam duc va thanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((ty nang) OR (ky nang)) ma hoi. ((hieu ve) or (hieu van)) cam duc va thanh vi cua tre*.