Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hieu vien » hieu viec, thieu nien, hieu tieng
cua viet » ca viet, hoa viet, cua vat
can cuoc » ca cuoc, cac cuoc, nhan cuoc
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
cuoc va » nuoc va, duoc va, quoc va
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
dai hoi » dai hoc, dai hai, dai moi
mai hoi » mai khoi, lai hoi, mai doi
ty nang » ky nang, ty xang, ty hang
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty nang ((mai hoi) or (dai hoi)). ((hieu vien) OR (hieu hien)) can cuoc va hanh di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ((mai hoi) OR (dai hoi)). ((hieu vien) OR (hieu hien)) can cuoc va hanh di cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ((mai hoi) or (dai hoi)). ((hieu vien) OR (hieu hien)) can cuoc va hanh di cua viet".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ((mai hoi) or (dai hoi)). ((hieu vien) OR (hieu hien)) can cuoc va hanh di cua viet*.