Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh hai » thanh hai, nhanh hai, hang hai
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ve cam » ve cham, ve cac, va cam
xuc va » duc va, tuc va, luc va

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 y nang ma hoa. hieu ve cam ((xuc va) or (thuc vat)) hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ma hoa. hieu ve cam ((xuc va) OR (thuc vat)) hanh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ma hoa. hieu ve cam ((xuc va) or (thuc vat)) hanh hai cua tre*.