Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
cau thuc » cau truc, cuu thuc, can thuc
dinh hai » dinh thai, tinh hai, dinh ha
hieu van » thien van, lieu va, hieu ve
hai cau » hai chau, hai chu, hai hau
va dinh » van dinh, va kinh, va tinh
thuc va » thuc vat, thuc dan, thuc day
su sach » vu sach
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
so sach » so sanh, bo sach, co 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) OR (hieu va)) cau thuc va dinh 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) OR (hieu va)) cau thuc va dinh 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) OR (hieu va)) cau thuc va dinh hai cau triet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) y nang xa hoi. ((hieu van) OR (hieu va)) cau thuc va dinh hai cau triet*.