Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
hieu van » hieu va, thien van, hieu ve
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, dang xay, lang van
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
ha duc » ho duc, ha dac, xa duc
ha tuc » ha thuc, va tuc, thai tuc

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: su sach ky lang xa hoi. ((hieu van) OR (lieu va)) ((ha tuc) OR (ha duc)) van hanh tai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky lang xa hoi. ((hieu van) OR (lieu va)) ((ha tuc) or (ha duc)) van hanh tai cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ky lang xa hoi. ((hieu van) OR (lieu va)) ((ha tuc) or (ha duc)) van hanh tai cua tre*.