Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach tru » sach truc, sach thu, sach tu
tru nang » tra nang, tri nang, truc nano
lai cua » dai cua, hai cua, lai chau
vai cua » dai cua, hai cua, bai cua
va danh » va dinh, va hanh, dia danh
qua cac » cua cac
va dan » ca dan, va dao, va dau
cac su » cach su, cac sau, cac du
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach tru nang x hoi. hieu qua cac su ((va danh) or (va dan)) ((vai cua) or (lai cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tru nang x hoi. hieu qua cac su ((va danh) OR (va dan)) ((vai cua) OR (lai cua)) te.
• Adding a wildcard symbol may retrieve word variants: toc sach tru nang x hoi. hieu qua cac su ((va danh) or (va dan)) ((vai cua) or (lai cua)) te*.