Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh va » hang va, hanh vi
sach ty » sach y, sach tu, sach thu
su sach » so sach, vu sach
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, xa hoi, me hoi
xuc va » duc va, tuc va, luc va
va cua » va chua, via cua, ca cua
cua te » cua tu

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) OR (ma hoa)). hieu van nam ((xuc va) OR (thuc vat)) hanh va cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ((ma hoi) OR (ma hoa)). hieu van nam ((xuc va) or (thuc vat)) hanh va cua te~".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ((ma hoi) OR (ma hoa)). hieu van nam ((xuc va) or (thuc vat)) hanh va cua te*.