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
cua tre » cua te, cuu tre, cua triet
tu sac » tu cac, tu san, tu bac
tu ban » thu ban, te ban
vi cua » vai cua, di 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 sac) OR (tu sach))) or (tu ban)) ky nang x hoi. hieu van tham thuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((tu sac) OR (tu sach))) OR (tu ban)) ky nang x hoi. hieu van tham thuc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((tu sac) OR (tu sach))) or (tu ban)) ky nang x hoi. hieu van tham thuc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((((tu sac) OR (tu sach))) or (tu ban)) ky nang x hoi. hieu van tham thuc va hanh vi cua tre*.