Perhaps you should try some spelling variations:
cam truc » cau truc, nam truc, lam truoc
dai hoi » dai hoc, dai hai, dai moi
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
qua cam » qua cham, qua cac, qua ca
cua tre » cua te, cuu tre, cua triet
mai hoi » mai khoi, lai hoi, mai doi
sach v » sach va, sach 2, sach vay
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: te ((sach v) or (sach y)) nang ((mai hoi) OR (dai hoi)). hieu qua cam truc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach v) OR (sach y)) nang ((mai hoi) OR (dai hoi)). hieu qua cam truc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach v) or (sach y)) nang ((mai hoi) OR (dai hoi)). hieu qua cam truc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach v) or (sach y)) nang ((mai hoi) OR (dai hoi)). hieu qua cam truc va hanh vi cua tre*.