Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
ban thanh » ban hanh, ban hang
ve triet » su triet
va trien » va truyen, va thiet, va tuyen
hieu van » thien van, lieu va, hieu ve
duc ban » duc tan, duc van, dua ban
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cau duc » cao duc, cau luc, chu duc
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang o hoi. ((hieu van) OR (hieu va)) cau duc ban thanh tai ((va trien) or (ve triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang o hoi. ((hieu van) OR (hieu va)) cau duc ban thanh tai ((va trien) OR (ve triet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang o hoi. ((hieu van) OR (hieu va)) cau duc ban thanh tai ((va trien) or (ve triet))*".