Perhaps you should try some spelling variations:
doanh dai » doanh tai, doanh dao, doanh giai
ban doanh » van doanh, san doanh, ban danh
te sach » toc sach
dan tay » ban tay, dao tay, gian tay
hieu ve » hieu van
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
duc ban » duc tan, duc van, dua ban
cua tre » cua te, cuu tre, cua triet

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 y ((dung tai) or (dan tay)) hoi. ((hieu ve) OR (hieu va)) cac duc ban doanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y ((dung tai) OR (dan tay)) hoi. ((hieu ve) OR (hieu va)) cac duc ban doanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y ((dung tai) or (dan tay)) hoi. ((hieu ve) OR (hieu va)) cac duc ban doanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach y ((dung tai) or (dan tay)) hoi. ((hieu ve) OR (hieu va)) cac duc ban doanh dai cua tre*.