Perhaps you should try some spelling variations:
thanh toan » thanh hoa, thanh san, tinh toan
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
duc manh » suc manh, duc anh, duc minh
duc van » duc va, duc tan, duc phan
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach v nang x hoi. hieu van ban ((duc van) OR (duc manh)) thanh toan ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach v nang x hoi. hieu van ban ((duc van) OR (duc manh)) thanh toan ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach v nang x hoi. hieu van ban ((duc van) OR (duc manh)) thanh toan ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: thu sach v nang x hoi. hieu van ban ((duc van) OR (duc manh)) thanh toan ((cua tre) or (cuu tre))*.