Perhaps you should try some spelling variations:
nang tai » hang tai, tang tai, sang tai
tu sach » thu sach, su sach, te sach
hieu va » lieu va
thue va » thuyet va, thuc vat, thuat va
thuc va » thuc vat, thuc dan, thuc day
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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 x hoi. ((hieu va) OR (hieu qua)) cam ((thue va) or (thuc va)) nang tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang x hoi. ((hieu va) OR (hieu qua)) cam ((thue va) OR (thuc va)) nang tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang x hoi. ((hieu va) OR (hieu qua)) cam ((thue va) or (thuc va)) nang tai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang x hoi. ((hieu va) OR (hieu qua)) cam ((thue va) or (thuc va)) nang tai cua tre*.