Perhaps you should try some spelling variations:
hai truc » dai truc, hai trac, hang truc
xay hoi » xa hoi, cay phoi, gay thoi
tay hoi » tay ho, tao hoi, tay thai
sach ky » sac ky, sach y, sach ty
qua hai » qua hoat
ky dang » ky nang, ky danh
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
so sach » so sanh, bo sach, co sach
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 dang ((xay hoi) OR (tay hoi)). hieu qua hai truc va hanh ((vi cua) OR (di cua)) triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky dang ((xay hoi) OR (tay hoi)). hieu qua hai truc va hanh ((vi cua) or (di cua)) triet~".
• Adding a wildcard symbol may retrieve word variants: so sach ky dang ((xay hoi) OR (tay hoi)). hieu qua hai truc va hanh ((vi cua) or (di cua)) triet*.