Perhaps you should try some spelling variations:
lam truc » lam truoc, nam truc, lam thuoc
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
van lam » van nam
truc va » thuc va, thuc vat, trung va
va tinh » may tinh
tinh di » tinh doi, trinh di, tinh da
y nang » ky nang, ly nang, v nang
so hai » son hai, su hai, co hai
di cua » dai cua, doi cua, de cua
cua te » cua tu
so ha » so hoa, so va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y nang ((so hai) OR (so ha)). hieu van lam truc va tinh di cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang ((so hai) OR (so ha)). hieu van lam truc va tinh di cua te".
• Adding a wildcard symbol may retrieve word variants: so sach y nang ((so hai) OR (so ha)). hieu van lam truc va tinh di cua te*.