Perhaps you should try some spelling variations:
van trieu » tan trieu, van tieu, van hieu
cac nuoc » cap nuoc, hoc nuoc, cua nuoc
thanh vi » hanh vi, thanh va, thanh ve
hieu van » hieu va, thien van, lieu va
hanh ve » hanh vi, hanh va, hanh kem
te sach » toc sach
sach ty » sach y, sach tu, sach thu
xang x » nang x
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: te sach ty xang x hoi. hieu van ((cac nuoc) OR (dat nuoc)) va ((thanh vi) or (hanh ve)) van trieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty xang x hoi. hieu van ((cac nuoc) OR (dat nuoc)) va ((thanh vi) OR (hanh ve)) van trieu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty xang x hoi. hieu van ((cac nuoc) OR (dat nuoc)) va ((thanh vi) or (hanh ve)) van trieu".
• Adding a wildcard symbol may retrieve word variants: te sach ty xang x hoi. hieu van ((cac nuoc) OR (dat nuoc)) va ((thanh vi) or (hanh ve)) van trieu*.