Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
van cam » van nam, van lam, van cau
hanh di » hanh vi, hanh de, hang di
y nang » ly nang, v nang, may nang
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa
di cua » dai cua, doi cua, de 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: tu sach ((y nang) OR (ky nang)) x hoi. hieu van cam ((xuc va) or (tuc va)) hanh di cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (ky nang)) x hoi. hieu van cam ((xuc va) OR (tuc va)) hanh di cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) OR (ky nang)) x hoi. hieu van cam ((xuc va) or (tuc va)) hanh di cua vat".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) OR (ky nang)) x hoi. hieu van cam ((xuc va) or (tuc va)) hanh di cua vat*.