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

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 - anh ((tang cua) or (tang luan)) dung cong ((dan toan) or (dan than)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo kha nang - anh ((tang cua) OR (tang luan)) dung cong ((dan toan) OR (dan than)) cau.
• Adding a wildcard symbol may retrieve word variants: theo kha nang - anh ((tang cua) or (tang luan)) dung cong ((dan toan) or (dan than)) cau*.