Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
cham hoc » cham soc, chat hoc, cham hoi
hieu van » thien van, lieu va, hieu ve
van nang » van quang, van ban, van dong
cua viet » ca viet, hoa viet, cua vat
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
vai cua » dai cua, hai cua, lai cua

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) OR (su sach)) van nang xa hoi. ((hieu van) OR (hieu va)) cham hoc va hanh vai cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (su sach)) van nang xa hoi. ((hieu van) OR (hieu va)) cham hoc va hanh vai cua viet~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (su sach)) van nang xa hoi. ((hieu van) OR (hieu va)) cham hoc va hanh vai cua viet*.