Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
day thanh » dao thanh, dat thanh, da thanh
day manh » van manh, duc manh, ha manh
sach ly » sach y, sach lo, sach ty
vu sach » vu bach, su sach, vu khach
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
ly nang » ky nang, ly hang, ly vang
cua tre » cua te, cuu tre, cua triet
de cua » le cua, te cua, dieu cua
x hoi » o hoi, x ho, 5 hoi

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 ly nang ((x hoi) OR (xa hoi)). hieu ve cham thuc ((day manh) or (day thanh)) de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ly nang ((x hoi) OR (xa hoi)). hieu ve cham thuc ((day manh) OR (day thanh)) de cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ly nang ((x hoi) OR (xa hoi)). hieu ve cham thuc ((day manh) or (day thanh)) de cua tre*".