Perhaps you should try some spelling variations:
vanh dai » van dai, vanh tai, lanh dao
thuc dan » thuc hanh, hoc dan, thuc vat
tu sach » thu sach, te sach, tu cach
thuc va » thuc vat, thuc day
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
nang o » nang co, nang ho, nang ro
va cam » va cham, va cac, va cao
o hai » co hai, so hai, o lai

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang o hai. hieu va cam ((thuc va) OR (thuc dan)) vanh dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky nang o hai. hieu va cam ((thuc va) OR (thuc dan)) vanh dai cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang o hai. hieu va cam ((thuc va) OR (thuc dan)) vanh dai cua tre*.