Perhaps you should try some spelling variations:
sach nganh » sach ngan, cac nganh, cach nhanh
sach tranh » canh tranh
sach danh » sach dao, sach dung, sach kinh
tranh ky » trinh ky, thanh ky, hanh ky
thuat co » thuat do, thuat o
ly huyet » ly thuyet, li thuyet, ly chuyen
huyet va » thuyet va, quyet van, huyen van
te sach » toc sach
va hoc » van hoc

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 ky thuat co hoc ) OR ( te ((sach nganh) OR (sach danh)) ly huyet va hoc ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach tranh ky thuat co hoc ) or ( te ((sach nganh) OR (sach danh)) ly huyet va hoc ))~".
• Adding a wildcard symbol may retrieve word variants: (( te sach tranh ky thuat co hoc ) or ( te ((sach nganh) OR (sach danh)) ly huyet va hoc ))*.