Perhaps you should try some spelling variations:
sach tranh » canh tranh
tranh my » trinh my, tran sy, anh my
trinh ly » trinh ky, trinh do, trinh tu
te sach » toc sach
su sach » vu sach
so sach » so sanh, bo sach, co sach
my khi » ky khi, my chi
ly khi » ly 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: (( te sach tranh my khi đong luc ) OR ( ((su sach) OR (so sach)) trinh ly khi đong luc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach tranh my khi đong luc ) or ( ((su sach) OR (so sach)) trinh ly khi đong luc ))~".
• Adding a wildcard symbol may retrieve word variants: (( te sach tranh my khi đong luc ) or ( ((su sach) OR (so sach)) trinh ly khi đong luc ))*.