Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
theo kha » theo phap, thao khoa, theo chu
kha nang » phap nang, ky nang, ki nang
tang cua » mang cua, tang luan, thong cua
hang cua » mang cua, hang ca, huong cua
san toan » van toan, manh toan, xuan toan
dan toan » van toan, dan than, manh toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo kha nang - hanh ((tang cua) or (hang cua)) thong cong ((san toan) OR (dan toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo kha nang - hanh ((tang cua) OR (hang cua)) thong cong ((san toan) OR (dan toan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo kha nang - hanh ((tang cua) or (hang cua)) thong cong ((san toan) OR (dan toan)) cau".
• Adding a wildcard symbol may retrieve word variants: theo kha nang - hanh ((tang cua) or (hang cua)) thong cong ((san toan) OR (dan toan)) cau*.