Perhaps you should try some spelling variations:
hai truc » dai truc, hang truc, thai thuc
hai trac » hoi trac, khai thac, thai tran
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
ky danh » ky anh, ky dang
danh xa » danh ca, dinh xa, canh xa
va hanh » van hanh, va thanh, va danh
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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: so sach ky danh xa hoi. hieu qua ((hai truc) OR (hai trac)) va hanh ((vi cua) OR (di cua)) triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky danh xa hoi. hieu qua ((hai truc) OR (hai trac)) va hanh ((vi cua) or (di cua)) triet~".
• Adding a wildcard symbol may retrieve word variants: so sach ky danh xa hoi. hieu qua ((hai truc) OR (hai trac)) va hanh ((vi cua) or (di cua)) triet*.