Perhaps you should try some spelling variations:
theo chieu » theo tieu, ho chieu, theo chu
chieu xanh » chieu sach, chieu sang, chieu tinh
thong cong » trong cong, tong cong, thong thong
hanh tang » hanh trang, anh tang, hanh mang
tang luan » dung luan
nhung don » nhung van, nhung bo
bai toan » bai tap
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: theo chieu xanh - hanh tang luan ((nhung don) or (thong cong)) bai toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo chieu xanh - hanh tang luan ((nhung don) OR (thong cong)) bai toan cao*.