Perhaps you should try some spelling variations:
cac trung » cac truong, dac trung, bac trung
thanh vi » thanh va, thanh ve, nhanh vi
trung va » truong va, trang va, trung ha
sach ty » sach tu, sach thu, xach tay
su viet » so viet
hieu ve » hieu va, hieu van
xang x » nang x
ve cac » va cac, vien cac
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: vu ((sach ty) OR (sach y)) xang x hoi. hieu ve cac trung va ((thanh vi) or (hanh vi)) su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach ty) OR (sach y)) xang x hoi. hieu ve cac trung va ((thanh vi) OR (hanh vi)) su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu ((sach ty) OR (sach y)) xang x hoi. hieu ve cac trung va ((thanh vi) or (hanh vi)) su viet".
• Adding a wildcard symbol may retrieve word variants: vu ((sach ty) OR (sach y)) xang x hoi. hieu ve cac trung va ((thanh vi) or (hanh vi)) su viet*.