Perhaps you should try some spelling variations:
truc may » tren may, truc va
dien cuc » dien tu, dieu cua, vien cac
cuc tieu » muc tieu, cac tieu, cach tieu
bo sach » co sach, hoc sach
sach va » sach xa, sach ha, sach dao
va nang » van nang, da nang, cam nang
ma hoi » mai hoi, ma hoa, me hoi
va cam » va cham, va cac, va cai
va cao » va cac, va co, va dao
tinh » trinh, dinh, minh

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach va nang ((ma hoi) or (xa hoi)). lieu ((va cam) or (va cao)) truc may tinh dien cuc tieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach va nang ((ma hoi) OR (xa hoi)). lieu ((va cam) OR (va cao)) truc may tinh dien cuc tieu.
• Adding a wildcard symbol may retrieve word variants: bo sach va nang ((ma hoi) or (xa hoi)). lieu ((va cam) or (va cao)) truc may tinh dien cuc tieu*.