Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
thanh vi » thanh va, thanh ve, nhanh vi
sach thu » sach thue, sach thieu, sach tham
sach tu » cach tu, sach ty, sach uu
hieu ve » hieu va, hieu van
xang x » nang x
ve cac » va cac, vien cac
cac tu » cac thu, cach tu, cac du
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: so ((sach thu) or (sach tu)) xang x hoi. hieu ve cac tu va ((thanh vi) OR (hanh vi)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach thu) OR (sach tu)) xang x hoi. hieu ve cac tu va ((thanh vi) OR (hanh vi)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach thu) or (sach tu)) xang x hoi. hieu ve cac tu va ((thanh vi) OR (hanh vi)) su triet".
• Adding a wildcard symbol may retrieve word variants: so ((sach thu) or (sach tu)) xang x hoi. hieu ve cac tu va ((thanh vi) OR (hanh vi)) su triet*.