Perhaps you should try some spelling variations:
dieu cua » dieu tra
dien cua » dien cuc, dien cu, tien cua
vu sach » vu bach, su sach, vu khach
va danh » va dinh, va dan, va hanh
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
ve cac » va cac, vien cac
ma hoi » mai hoi, xa hoi, me hoi

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: vu sach ky tang ((ma hoi) OR (ma hoa)). hieu ve cac duc va danh ((dien cua) OR (dieu cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky tang ((ma hoi) or (ma hoa)). hieu ve cac duc va danh ((dien cua) OR (dieu cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: vu sach ky tang ((ma hoi) or (ma hoa)). hieu ve cac duc va danh ((dien cua) OR (dieu cua)) tre*.