Perhaps you should try some spelling variations:
sach khoa » bach khoa, sach nha, anh khoa
khoa toc » khoa hoc, hoa toc, khoa thuoc
toc tien » hoc tien, toc mien, toc stieng
tien khi » trien khai
gian don » gian dan, giang son, gian dien
tu sach » thu sach, su sach, te sach
khi cua » chi cua, thai cua
gi doc » giam doc, gian doc

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 khoa toc tien khi cua ets : nhung ((gi doc) OR (gian don)) vi đai~.
• Adding a wildcard symbol may retrieve word variants: tu sach khoa toc tien khi cua ets : nhung ((gi doc) or (gian don)) vi đai*.