Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
cac truc » cau truc, cac tru, cac trung
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
van cac » van hac, van cau, van bac
truc va » thuc va, thuc vat, trung va
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
y nang » ky nang, ly nang, v nang
di va » dai va, di vao, doi 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) or (hoc sach)) y nang xa hoi. hieu van cac truc va danh di va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (hoc sach)) y nang xa hoi. hieu van cac truc va danh di va triet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (hoc sach)) y nang xa hoi. hieu van cac truc va danh di va triet*.