Perhaps you should try some spelling variations:
thanh van » thanh toan, thanh phan, thanh nhan
cua triet » cua viet, su triet, va triet
thu sach » tu sach, thuat sach, thuoc sach
sach ty » sach y, sach tu, sach thu
qua cam » qua cham, qua cac, qua ca
cam tuc » cam xuc, cam tu, nam thuc
tuc va » thuc va, truc va, tuc xa
x hoi » xa hoi, o hoi, x ho
o hai » co hai, so hai, o lai

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 ty xang ((x hoi) or (o hai)). hieu qua cam tuc va ((thanh van) OR (thanh san)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty xang ((x hoi) OR (o hai)). hieu qua cam tuc va ((thanh van) OR (thanh san)) cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty xang ((x hoi) or (o hai)). hieu qua cam tuc va ((thanh van) OR (thanh san)) cua triet".
• Adding a wildcard symbol may retrieve word variants: thu sach ty xang ((x hoi) or (o hai)). hieu qua cam tuc va ((thanh van) OR (thanh san)) cua triet*.