Perhaps you should try some spelling variations:
hanh hai » thanh hai, nhanh hai, hang hai
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hai cua » thai cua, dai cua, hoi cua
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
xuc va » duc va, tuc va, luc va
ma hoi » mai hoi, ma hoa, me hoi
ve cam » ve cham, ve cac, va cam

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