Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
sach thu » sach thue, sach thieu, sach tham
sach tu » cach tu, sach ty, sach uu
duc ban » duc tan, duc van, dua ban
ca viet » va viet, co viet, hoa viet
va cam » va cham, va cac, va cao
xang x » nang x
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho
vi ca » vit ca, li ca, va ca

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach tu) OR (sach thu)) xang x hoi. hieu ((ve cac) or (va cam)) duc ban thanh vi ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach tu) OR (sach thu)) xang x hoi. hieu ((ve cac) OR (va cam)) duc ban thanh vi ca viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach tu) OR (sach thu)) xang x hoi. hieu ((ve cac) or (va cam)) duc ban thanh vi ca viet".
• Adding a wildcard symbol may retrieve word variants: su ((sach tu) OR (sach thu)) xang x hoi. hieu ((ve cac) or (va cam)) duc ban thanh vi ca viet*.