Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thanh toan » thanh hoa, thanh san, tinh toan
toan cua » than cua, tan cua, doanh cua
hieu van » hieu va, thien van, lieu va
dang dai » dang hai, dang bai, dang dan
hieu ve » hieu va
sach ky » sac ky, sach y, sach ty
dai hai » dai han, dai hoi, dai tai
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ky dang dai hai. ((hieu ve) or (hieu van)) cam ((xuc va) OR (luc va)) thanh toan cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky dang dai hai. ((hieu ve) OR (hieu van)) cam ((xuc va) OR (luc va)) thanh toan cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ky dang dai hai. ((hieu ve) or (hieu van)) cam ((xuc va) OR (luc va)) thanh toan cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky dang dai hai. ((hieu ve) or (hieu van)) cam ((xuc va) OR (luc va)) thanh toan cua tre*.