Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach tu » sach thu, cach tu, sach ty
lai cua » dai cua, hai cua, lai chau
vai cua » dai cua, hai cua, bai cua
tuc ban » thuc ban, truc ban, tuc dan
qua cac » cua cac
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano
tu ban » thu ban, te ban

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 tu nang xa hoi. hieu qua cac ((tuc ban) OR (tu ban)) hanh ((vai cua) or (lai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tu nang xa hoi. hieu qua cac ((tuc ban) OR (tu ban)) hanh ((vai cua) OR (lai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach tu nang xa hoi. hieu qua cac ((tuc ban) OR (tu ban)) hanh ((vai cua) or (lai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach tu nang xa hoi. hieu qua cac ((tuc ban) OR (tu ban)) hanh ((vai cua) or (lai cua)) tre*.