Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
cau thuc » cau truc, cuu thuc, can thuc
tinh vu » tinh va, tinh tu, tinh su
va tinh » may tinh
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, te sach, tu cach
hieu ve » hieu va, hieu van
cao hoi » cau hoi, co hoi, cao hoc
su sach » so sach, vu sach
y nang » ky nang, ly nang, v nang
vu va » vu van, tu va, su va

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

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