Perhaps you should try some spelling variations:
ban doan » ban doanh, ban dan, ban soan
sach kem » hanh kem
dang tay » dang xay, dung tay, dan tay
doan vi » doan va, don vi, doan thi
tay hoi » tay ho, tao hoi, tay thai
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cao, va cai
sac ky » cac ky, sai ky
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 kem) or (sac ky)) dang tay hoi. hieu ((va cam) OR (va cac)) cua ban doan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach kem) OR (sac ky)) dang tay hoi. hieu ((va cam) OR (va cac)) cua ban doan vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach kem) or (sac ky)) dang tay hoi. hieu ((va cam) OR (va cac)) cua ban doan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach kem) or (sac ky)) dang tay hoi. hieu ((va cam) OR (va cac)) cua ban doan vi cua tre*.