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