Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
hieu van » hieu va, thien van, lieu va
cau thuc » cau truc, cuu thuc, can thuc
nang xa » nang x, lang xa, nang ma
so sach » so sanh, bo sach, co sach
van cau » van dau, van hau, van chat
va dinh » van dinh, va kinh, vu dinh
va tinh » may tinh
hai cau » hai chau, hai chu, hai hau
su sach » vu sach
y nang » ky nang, ly nang, v nang

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 (so sach)) y nang xa hoi. hieu van cau thuc ((va dinh) OR (va tinh)) hai cau triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) y nang xa hoi. hieu van cau thuc ((va dinh) OR (va tinh)) hai cau triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) y nang xa hoi. hieu van cau thuc ((va dinh) OR (va tinh)) hai cau triet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) y nang xa hoi. hieu van cau thuc ((va dinh) OR (va tinh)) hai cau triet*.