Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, can thuc
dua tren » dung tren
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
cam thu » nam thu, cac thu, ca thu
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
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: su sach y nang x hoi. hieu ve ((cam thuc) OR (cam thu)) va hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x hoi. hieu ve ((cam thuc) OR (cam thu)) va hanh vi ((dua tren) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x hoi. hieu ve ((cam thuc) OR (cam thu)) va hanh vi ((dua tren) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. hieu ve ((cam thuc) OR (cam thu)) va hanh vi ((dua tren) or (cuu tre))*.