Perhaps you should try some spelling variations:
thuoc va » thuoc ma, thuong va, thuoc tai
hanh lai » hanh lam, hanh tai, thanh lap
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
va bach » va cach, vu bach, va bac
thuc va » thuc vat, thuc dan, thuc day
lai cua » dai cua, hai cua, lai chau
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, 5 hoi

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 ((x hoi) OR (x ho)). hieu va bach ((thuoc va) or (thuc va)) hanh lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((x hoi) OR (x ho)). hieu va bach ((thuoc va) OR (thuc va)) hanh lai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((x hoi) OR (x ho)). hieu va bach ((thuoc va) or (thuc va)) hanh lai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x hoi) OR (x ho)). hieu va bach ((thuoc va) or (thuc va)) hanh lai cua tre*.