Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
van cac » van hac, van cau, van bac
cuu tre » cua tre, cau tren, cau treo
duc ban » duc tan, duc van, dua ban
cac duc » cac du, cao duc, cac dac
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
dang do » nang doc, dang duc, dung doi
hang do » hang doi, hang di, hang du
cua te » cua tu

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 ty ((hang do) OR (dang do)) thoi. hieu van cac duc ban thanh tai ((cuu tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((hang do) OR (dang do)) thoi. hieu van cac duc ban thanh tai ((cuu tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((hang do) OR (dang do)) thoi. hieu van cac duc ban thanh tai ((cuu tre) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((hang do) OR (dang do)) thoi. hieu van cac duc ban thanh tai ((cuu tre) or (cua te))*.