Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
hanh hai » thanh hai, nhanh hai, hang hai
truc va » thuc va, thuc vat, trung va
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
xuc va » duc va, tuc va, luc va
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: ((toc sach) OR (doc sach)) ky nang ma hoa. 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: ((toc sach) OR (doc sach)) ky nang ma hoa. 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: "((toc sach) OR (doc sach)) ky nang ma hoa. hieu ve cam ((xuc va) or (truc va)) hanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (doc sach)) ky nang ma hoa. hieu ve cam ((xuc va) or (truc va)) hanh hai cua tre*.