Perhaps you should try some spelling variations:
sach ngan » sach ngon, sach nha, sach nang
sach han » sach tham, sach danh, sach nang
ngan goc » ngan gon, nguon goc, nganh soc
tu sach » thu sach, te sach, tu cach
cho khi » co khi, cao khai, chat khi
su sach » so sach, vu sach
goc khi » hoc khi, ngoc khoi, goc nhin

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: (( tu sach han ((cho khi) OR (cho ghi)) đong luc ) OR ( su sach ngan goc khi đong luc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach han ((cho khi) OR (cho ghi)) đong luc ) or ( su sach ngan goc khi đong luc ))~".
• Adding a wildcard symbol may retrieve word variants: (( tu sach han ((cho khi) OR (cho ghi)) đong luc ) or ( su sach ngan goc khi đong luc ))*.