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