Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
ha tuc » ha thuc, va tuc, thai tuc
ha duc » ho duc, ha dac, hoa duoc
xa duc » xuan duc
ma hoi » mai hoi, xa hoi, ma hoa

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