Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh hai » thanh hai, nhanh hai, hang hai
su triet » su viet, su tien, ve triet
sach ty » sach y, sach tu, sach thu
chuc va » thuc va
ty nang » ky nang, ty xang, ty hang
hieu vi » hieu voi, hieu va, hieu ve
ma hoi » mai hoi, ma hoa, me hoi
hai su » hai vu, lai su, hai so

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: toc sach ty nang ((ma hoi) OR (xa hoi)). hieu vi pham ((chuc va) OR (thuc vat)) hanh hai su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty nang ((ma hoi) or (xa hoi)). hieu vi pham ((chuc va) OR (thuc vat)) hanh hai su triet~".
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang ((ma hoi) or (xa hoi)). hieu vi pham ((chuc va) OR (thuc vat)) hanh hai su triet*.