Perhaps you should try some spelling variations:
day nhanh » day thanh, duy nhanh, dac nhan
day hanh » day thanh, dao hanh, day manh
vu sach » vu bach, su sach, vu khach
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
vi cua » vai cua, di cua
x hoi » o hoi, x ho, 5 hoi
ve am » va am

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach v nang ((x hoi) or (xa hoi)). hieu ve am thuc ((day hanh) OR (day nhanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach v nang ((x hoi) OR (xa hoi)). hieu ve am thuc ((day hanh) OR (day nhanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach v nang ((x hoi) or (xa hoi)). hieu ve am thuc ((day hanh) OR (day nhanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach v nang ((x hoi) or (xa hoi)). hieu ve am thuc ((day hanh) OR (day nhanh)) vi cua tre*.