Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
hieu van » hieu va, thien van, lieu va
vat hanh » vat thanh, van hanh, va hanh
van cau » van dau, van hau, van chat
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
vi cua » vai cua, di cua
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: thu ((sac ky) or (sach y)) nang ((x hoi) or (x ho)). hieu van cau thuc vat hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sac ky) OR (sach y)) nang ((x hoi) OR (x ho)). hieu van cau thuc vat hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: thu ((sac ky) or (sach y)) nang ((x hoi) or (x ho)). hieu van cau thuc vat hanh vi cua tre*.