Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
mot chieu » doi chieu
hanh tang » hanh trang, anh tang, hanh tung
hanh mang » nhanh mang, hanh trang, nhanh lang
cua nhung » va nhung
ho chieu » theo chieu, hoc thieu, doi chieu
cong bai » cuong bai, cong hai, cung bai
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: ((mot chieu) or (ho chieu)) xanh - ((hanh tang) OR (hanh mang)) cua nhung cong bai toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((mot chieu) OR (ho chieu)) xanh - ((hanh tang) OR (hanh mang)) cua nhung cong bai toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((mot chieu) or (ho chieu)) xanh - ((hanh tang) OR (hanh mang)) cua nhung cong bai toan cao".
• Adding a wildcard symbol may retrieve word variants: ((mot chieu) or (ho chieu)) xanh - ((hanh tang) OR (hanh mang)) cua nhung cong bai toan cao*.