Perhaps you should try some spelling variations:
thien bang » khien bang, thien dang, thien nang
thien ban » thien van, phien ban, khien ban
hieu van » hieu va, thien van, lieu va
dua tren » dung tren
va hanh » van hanh, va thanh, va danh
van cam » van nam, van lam, van cau
su sach » so sach, vu sach
cuu tre » cua tre, cau tren, cau treo
xuc va » duc va, tuc va, luc va

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 ((thien bang) or (thien ban)) xa hoi. hieu van cam xuc va hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((thien bang) OR (thien ban)) xa hoi. hieu van cam xuc va hanh vi ((dua tren) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: su sach ((thien bang) or (thien ban)) xa hoi. hieu van cam xuc va hanh vi ((dua tren) or (cuu tre))*.