Perhaps you should try some spelling variations:
sach tranh » canh tranh
tranh chai » tranh chap, tranh cai, tranh thai
tien chat » tieng nhat, tinh chat, tien mat
chai khoa » thai khoa, chi khoa, pham khoa
tien cua » trien cua, tiep cua, dien cua
tu sach » thu sach, su sach, tu cach
te sach » toc sach

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 ((tien chat) OR (tien cua)) hoa hoc ) OR ( te sach tranh chai khoa hoc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach ((tien chat) OR (tien cua)) hoa hoc ) or ( te sach tranh chai khoa hoc ))~".
• Adding a wildcard symbol may retrieve word variants: (( tu sach ((tien chat) OR (tien cua)) hoa hoc ) or ( te sach tranh chai khoa hoc ))*.