Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
sach thu » sach thue, sach thieu, sach tham
cau duc » cao duc, cau luc, chu duc
su sach » so sach, vu sach
tang ma » mang may, tang van
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
ve cau » ke cau, va cau, ve cac
vi ve » va ve, ve ve, vi he
gi ve » gia ve, gi de, gi he

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: su sach thu ((nang xa) OR (tang ma)) hoi. hieu ve cau duc va thanh ((vi ve) OR (gi ve)) triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thu ((nang xa) or (tang ma)) hoi. hieu ve cau duc va thanh ((vi ve) OR (gi ve)) triet~".
• Adding a wildcard symbol may retrieve word variants: su sach thu ((nang xa) or (tang ma)) hoi. hieu ve cau duc va thanh ((vi ve) OR (gi ve)) triet*.