Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
cua viet » hoa viet, cua vat, cua dieu
can nuoc » cap nuoc, cac nuoc, can cuoc
vien can » vien canh, vien cac, vien cao
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
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
ca viet » va viet, co viet, hoa viet

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 can nuoc va hanh di ((cua viet) or (ca 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 can nuoc va hanh di ((cua viet) OR (ca viet)).
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ((mai hoi) or (dai hoi)). hieu vien can nuoc va hanh di ((cua viet) or (ca viet))*.