Perhaps you should try some spelling variations:
sach nganh » cac nganh, sach danh, cach nhanh
sach tranh » canh tranh
thuyet toc » thuyet truoc, thuyet thuc, thuyet thoi
sach ngan » sach ngon, sach nha, sach han
tranh my » trinh my, tran sy, anh my
my thuat » ky thuat, ki thuat, va thuat
su sach » so sach, vu sach
toc hoc » toan hoc, duoc hoc
toan » tran

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( su sach tranh my thuat toan khoa ) or ( su ((sach nganh) OR (sach ngan)) ly thuyet toc hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach tranh my thuat toan khoa ) OR ( su ((sach nganh) OR (sach ngan)) ly thuyet toc hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( su sach tranh my thuat toan khoa ) or ( su ((sach nganh) OR (sach ngan)) ly thuyet toc hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( su sach tranh my thuat toan khoa ) or ( su ((sach nganh) OR (sach ngan)) ly thuyet toc hoc ))*.