Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, hieu cach
hoc thieu » toc thieu, hoc hien
nang cong » nang song, dang cong, bang cong
hang van » hoang van, dang van, tang van
cong san » cong tac
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: hoc thieu sach - hanh ((hang van) or (hang va)) nang cong san toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu sach - hanh ((hang van) OR (hang va)) nang cong san toan cao.
• Adding a wildcard symbol may retrieve word variants: hoc thieu sach - hanh ((hang van) or (hang va)) nang cong san toan cao*.