Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
mai khoi » mai khoa, tai khoa, cac khoi
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va, hieu van
ty nang » ky nang, ty xang, ty hang
mai hoi » dai hoi, lai hoi, mai doi
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
cam tu » cam thu, nam tu, dam tu
tu gia » tu giao, tu giac, tu giay
anh vi » hanh vi, anh va, anh vu
anh ve » hanh ve, anh va, anh viet

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 ty nang ((mai hoi) OR (mai khoi)). hieu ve cam tu gia ((anh vi) or (anh ve)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang ((mai hoi) OR (mai khoi)). hieu ve cam tu gia ((anh vi) OR (anh ve)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty nang ((mai hoi) OR (mai khoi)). hieu ve cam tu gia ((anh vi) or (anh ve)) cua tre*".