Perhaps you should try some spelling variations:
thieu sach » chieu sach, hieu cach, theo sach
thien hach » thien thanh, hien hanh
hanh trinh » canh tranh, hanh chinh
trinh luan » trinh luat, trinh quan, trinh han
luan vung » luan hung, luan ung, luan chung
vung song » vung dong, xuong song, nang song
song van » hoang van, trong van, duong van
ban cau » bang cau, ban can, van cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu sach) or (thien hach)) - hanh trinh luan vung song van ban cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (thien hach)) - hanh trinh luan vung song van ban cau*.