Perhaps you should try some spelling variations:
thi hang » thi hanh, thi nang, thi hong
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
thuc ban » thuoc ban, thuc dan, thu ban
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
ty lang » tay lang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (vu bach)) ((ty lang) or (thi hang)) xa hoi. hieu van nam thuc ban hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu bach)) ((ty lang) OR (thi hang)) xa hoi. hieu van nam thuc ban hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu bach)) ((ty lang) or (thi hang)) xa hoi. hieu van nam thuc ban hanh vi cua tre*.