Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien can » vien canh, vien cac, vien cao
quoc va » nuoc va, duoc va, quoc gia
cuoc va » nuoc va, duoc va, luoc va
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
dai moi » doi moi, dai hoi
mai hoi » mai khoi, dai hoi, lai hoi
ty nang » ky nang, ty xang, ty hang
vi hoa » voi hoa, vi hoc, va hoa

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 moi)). hieu vien can ((cuoc va) OR (quoc va)) hanh vi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ((mai hoi) OR (dai moi)). hieu vien can ((cuoc va) OR (quoc va)) hanh vi hoa viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ((mai hoi) or (dai moi)). hieu vien can ((cuoc va) OR (quoc va)) hanh vi hoa viet*".