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 dau » theo mau, thau dau, te dau
dau sach » cau sach, dat sach, hau sach
san van » tan van, luan van, tran van

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo dau sach - hanh trinh luan ((bang cong) or (hang nong)) san van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo dau sach - hanh trinh luan ((bang cong) OR (hang nong)) san van ban.
• Adding a wildcard symbol may retrieve word variants: theo dau sach - hanh trinh luan ((bang cong) or (hang nong)) san van ban*.