Perhaps you should try some spelling variations:
sach truc » sach tren, sach thu, sach thue
cach thuc » anh thuc, cac thu
hieu van » hieu va, thien van, lieu va
nano bac » tao bac, bang bac, dan bac
cuu ban » cua ban, cuu san, cuu nang
van cam » van nam, van lam, van cau
bac hoi » bac ho, bac hoc, sach hoi
cua tre » cua te, cuu tre, cua triet
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 truc) or (cach thuc)) nano bac hoi. hieu van cam ((cuu ban) or (cuu van)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach truc) OR (cach thuc)) nano bac hoi. hieu van cam ((cuu ban) OR (cuu van)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach truc) or (cach thuc)) nano bac hoi. hieu van cam ((cuu ban) or (cuu van)) hanh vi cua tre*.