Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, can thuc
su sach » so sach, vu sach
hanh di » hanh vi, hanh de, hang di
va hanh » van hanh, va thanh, va danh
cam thu » nam thu, cac thu, ca thu
hieu ve » hieu va
cuu tre » cua tre, cau tren, cau treo
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
di cuu » di cau, di cua, dinh 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: su sach v nang x hoi. ((hieu ve) or (hieu van)) ((cam thuc) OR (cam thu)) va hanh di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v nang x hoi. ((hieu ve) OR (hieu van)) ((cam thuc) OR (cam thu)) va hanh di cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v nang x hoi. ((hieu ve) or (hieu van)) ((cam thuc) OR (cam thu)) va hanh di cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sach v nang x hoi. ((hieu ve) or (hieu van)) ((cam thuc) OR (cam thu)) va hanh di cuu tre*.