Perhaps you should try some spelling variations:
thuong cong » thong cong, thuong con, thuong dong
hoc thieu » toc thieu, hoc hien
tranh cua » doanh cua, manh cua
tong cong » trong cong, cong cong, dung cong
ho chieu » theo chieu, doi chieu, mot chieu
bai toan » bai tap
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((ho chieu) OR (hoc thieu)) sach - canh tranh cua ((thuong cong) or (tong cong)) bai toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (hoc thieu)) sach - canh tranh cua ((thuong cong) OR (tong cong)) bai toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) OR (hoc thieu)) sach - canh tranh cua ((thuong cong) or (tong cong)) bai toan cau".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) OR (hoc thieu)) sach - canh tranh cua ((thuong cong) or (tong cong)) bai toan cau*.