Perhaps you should try some spelling variations:
sach nganh » sach ngan, cac nganh, sach danh
sach tranh » canh tranh
cong thai » cong hai, hong thai, cong thanh
tranh my » trinh my, tran sy, anh my
cong khi » khong khi, co khi, cong ha
su sach » so sach, vu sach
my khi » ly khi, ky khi, my chi

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