Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
hieu va » lieu va, hieu qua
xuc van » luc van, vuc van, xuc ban
duc van » duc va, duc tan, duc manh
hanh ve » hanh vi, hanh va, hanh kem
y nang » ky nang, ly nang, v nang
ve cua » le cua, de cua, te cua
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 y nang x hoi. ((hieu van) or (hieu va)) cam ((xuc van) OR (duc van)) hanh ve cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang x hoi. ((hieu van) OR (hieu va)) cam ((xuc van) OR (duc van)) hanh ve cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang x hoi. ((hieu van) or (hieu va)) cam ((xuc van) OR (duc van)) hanh ve cua vat".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang x hoi. ((hieu van) or (hieu va)) cam ((xuc van) OR (duc van)) hanh ve cua vat*.