Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
hanh ca » hanh cac, hanh cat, hanh cua
van cau » van dau, van hau, van chat
su sach » so sach
cao hoi » cau hoi, co hoi, cao hoc
vu sach » vu bach, vu khach
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa
ca cua » co cua

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) OR (vu sach)) ky nang cao hoi. hieu van cau ((xuc va) or (tuc va)) hanh ca cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) ky nang cao hoi. hieu van cau ((xuc va) OR (tuc va)) hanh ca cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (vu sach)) ky nang cao hoi. hieu van cau ((xuc va) or (tuc va)) hanh ca cua triet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (vu sach)) ky nang cao hoi. hieu van cau ((xuc va) or (tuc va)) hanh ca cua triet*.