Perhaps you should try some spelling variations:
mai khoi » mai khoa, tai khoa, cac khoi
sach dao » lanh dao
cam truc » cau truc, nam truc, lam truoc
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
sach lo » sach doi, sach hoi, sach moi
mai hoi » dai hoi, lai hoi, mai doi
ve cam » ve cham, ve cac, va cam
vi cua » vai cua, di cua

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