Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach tranh, cac nganh
nganh cong » nhanh chong, thanh cong
cong khi » cong thai, khong khi, co khi
bo sach » co sach, hoc sach
su can » su van, tu can, su han
su cao » cu cao, vu cao, su co
y khi » ly khi, ky khi, my khi

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: (( bo sach nganh y khi đong luc ) OR ( ((su can) OR (su cao)) nganh cong khi đong luc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( bo sach nganh y khi đong luc ) or ( ((su can) OR (su cao)) nganh cong khi đong luc ))~".
• Adding a wildcard symbol may retrieve word variants: (( bo sach nganh y khi đong luc ) or ( ((su can) OR (su cao)) nganh cong khi đong luc ))*.