Perhaps you should try some spelling variations:
duc ngan » duc ngon, duc nhan, luc ngan
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, vu khach
hang vi » hang va, hanh vi, hang di
lam duc » lam duoc, pham duc, nam duoc
van lam » van nam
ty hang » ly hang, thi hang, thu hang
su sach » so sach
vi cua » vai cua, di cua
cua te » cua tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sach) OR (su sach)) ((ty hang) or (ty xang)) xa hoi. hieu van lam duc ngan hang vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (su sach)) ((ty hang) OR (ty xang)) xa hoi. hieu van lam duc ngan hang vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) OR (su sach)) ((ty hang) or (ty xang)) xa hoi. hieu van lam duc ngan hang vi cua te".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) OR (su sach)) ((ty hang) or (ty xang)) xa hoi. hieu van lam duc ngan hang vi cua te*.