Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
trinh luan » trinh luat, trinh quan, trinh han
bang cong » dang cong, bang song, hang cong
hang nong » thang long, han tong
theo cau » theo chu, theo cap, theo dau
cau sach » cao sach, hau sach, rau sach
san toan » van toan, dan toan, manh toan
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 cau sach - hanh trinh luan ((bang cong) or (hang nong)) san toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo cau sach - hanh trinh luan ((bang cong) OR (hang nong)) san toan cao.
• Adding a wildcard symbol may retrieve word variants: theo cau sach - hanh trinh luan ((bang cong) or (hang nong)) san toan cao*.