Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien sach » vien bach, dien sach, viet sach
sach nuoc » sach duoc, cac nuoc, bach tuoc
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
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 y nang xa hoi. hieu vien sach nuoc ((va hanh) or (va danh)) de ((cua triet) OR (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang xa hoi. hieu vien sach nuoc ((va hanh) OR (va danh)) de ((cua triet) OR (va triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang xa hoi. hieu vien sach nuoc ((va hanh) or (va danh)) de ((cua triet) OR (va triet))".
• Adding a wildcard symbol may retrieve word variants: su sach y nang xa hoi. hieu vien sach nuoc ((va hanh) or (va danh)) de ((cua triet) OR (va triet))*.