Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
hanh tai » thanh tai, hang tai, han tai
tai cua » thai cua, tai cuc, tri cua
duc van » duc va, duc tan, duc manh
xuc van » luc van, vuc van, xuc ban
hieu va » lieu va, hieu qua
nang co » nang cao, nang doc, nang noi
ly nang » ky nang, ly hang, ly vang
va cao » va cac, va co, va dao
co hoi » co hoc, co loi
cua tu » cua tuc, cua su, cua cu

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 (doc sach)) ly nang co hoi. hieu va cao ((xuc van) OR (duc van)) hanh tai cua tu~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ly nang co hoi. hieu va cao ((xuc van) OR (duc van)) hanh tai cua tu~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ly nang co hoi. hieu va cao ((xuc van) OR (duc van)) hanh tai cua tu*.