Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
nang cho » nang chon, ngang cho, nang cao
doc sach » hoc sach, nuoc sach, dac sac
ty nang » ky nang, ty xang, ty hang
cho hoc » co hoc, khoa hoc
hieu va » lieu va, hieu qua
xuc ban » cuc ban, quoc ban, xuat ban
duc ban » duc tan, duc van, dua ban
hanh di » hanh vi, hanh de, hang di
di cua » dai cua, doi cua, de cua

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) OR (doc sach)) ty nang cho hoc. hieu va cac ((xuc ban) or (duc ban)) hanh di cua cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ty nang cho hoc. hieu va cac ((xuc ban) OR (duc ban)) hanh di cua cac*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) ty nang cho hoc. hieu va cac ((xuc ban) or (duc ban)) hanh di cua cac*".