Perhaps you should try some spelling variations:
hieu quan » lieu quan, thien quan, lien quan
thu sach » tu sach, thuat sach, thuoc sach
sach doi » sach hoi, sach moi, sach dao
doi nang » dai nang, hoi nang, voi nang
cau thuc » cau truc, cuu thuc, can thuc
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu
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: thu sach doi nang x hoi. ((((hieu ve) or (hieu quan))) or (hieu qua)) cau thuc va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach doi nang x hoi. ((((hieu ve) OR (hieu quan))) OR (hieu qua)) cau thuc va hanh vi cuu tre.
• Adding a wildcard symbol may retrieve word variants: thu sach doi nang x hoi. ((((hieu ve) or (hieu quan))) or (hieu qua)) cau thuc va hanh vi cuu tre*.