Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
sach tin » sach tien, sach kinh, sach tren
tin mang » tin nang, ninh mang, tien manh
su sach » so sach, vu sach
va tinh » may tinh
va dinh » van dinh, va kinh, vu dinh
va hanh » van hanh, va thanh, va danh
va cham » va chat, va tham
hieu va » lieu va, hieu qua
mang xa » lang xa, mang may, dang xay
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach tin mang xa hoi. hieu va cham thuc ((va hanh) or (((va dinh) or (va tinh)))) tri cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tin mang xa hoi. hieu va cham thuc ((va hanh) OR (((va dinh) OR (va tinh)))) tri cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach tin mang xa hoi. hieu va cham thuc ((va hanh) or (((va dinh) or (va tinh)))) tri cua tre*.