Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hieu van » thien van, lieu va, hieu ve
cam thuc » am thuc, nam thuc, cam thu
nang xa » nang x, lang xa, nang ma
va nang » van nang, da nang, cam nang
hieu va » lieu va, hieu qua
sach va » sach xa, sach ha, sach dao
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach

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 va nang xa hoi. ((hieu van) or (hieu va)) cam thuc va hanh di ((cua tre) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach va nang xa hoi. ((hieu van) OR (hieu va)) cam thuc va hanh di ((cua tre) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: su sach va nang xa hoi. ((hieu van) or (hieu va)) cam thuc va hanh di ((cua tre) or (su triet))*.