Perhaps you should try some spelling variations:
thien van » thi van
dai tren » dat tren, dau tren, dan tren
thanh vi » hanh vi, thanh va, thanh ve
hieu van » hieu va, lieu va, hieu ve
sach ky » sac ky, sach y, sach ty
soc ban » hoc ban, coc ban, soc ba
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
te sach » toc sach
so ban » sao ban, so bang, co ban
vi dai » si dai, li dai, vien dai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky tang xa hoi. ((hieu van) OR (thien van)) tham ((soc ban) OR (so ban)) thanh vi dai tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky tang xa hoi. ((hieu van) or (thien van)) tham ((soc ban) OR (so ban)) thanh vi dai tren~".
• Adding a wildcard symbol may retrieve word variants: te sach ky tang xa hoi. ((hieu van) or (thien van)) tham ((soc ban) OR (so ban)) thanh vi dai tren*.