Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh hai » thanh hai, nhanh hai, hang hai
sach ky » sac ky, sach y, sach ty
hai cua » thai cua, dai cua, hoi cua
truc va » thuc va, thuc vat, trung va
ve cham » va cham, ve chat, vu cham
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, luc va
ve cam » ve cac, va cam, ve cai
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: toc sach ky nang ma hoi. hieu ((ve cam) OR (ve cham)) ((xuc va) or (truc va)) hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang ma hoi. hieu ((ve cam) OR (ve cham)) ((xuc va) OR (truc va)) hanh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang ma hoi. hieu ((ve cam) OR (ve cham)) ((xuc va) or (truc va)) hanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang ma hoi. hieu ((ve cam) OR (ve cham)) ((xuc va) or (truc va)) hanh hai cua tre*.