Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thai tuc » thai thuc, thai thuy, thai hoc
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hac tuc » thac toc
tai cua » thai cua, tri cua, dai cua
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 ky nang ma hoi. hieu van ((hac tuc) OR (thai tuc)) van hanh ((tai cua) OR (tai cuc)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ma hoi. hieu van ((hac tuc) OR (thai tuc)) van hanh ((tai cua) or (tai cuc)) tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. hieu van ((hac tuc) OR (thai tuc)) van hanh ((tai cua) or (tai cuc)) tre*.