Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
tu sach » thu sach, su sach, te sach
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
tu ban » thu ban, te ban
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) or (tu ban)) ky nang x hoi. hieu van tham thuc va hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (tu ban)) ky nang x hoi. hieu van tham thuc va hanh di cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (tu ban)) ky nang x hoi. hieu van tham thuc va hanh di cua tre*.