Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
ve triet » va trien, su triet
toan cau » toan cao, toan ban, toan tap
thanh la » thanh lap, thanh lam, thanh lan
duc ban » duc tan, duc van, dua ban
van dau » van dao, phan dau
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
van cau » van hau, van chat, van canh
ty nang » ky nang, ty xang, ty hang
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai
la ve » ly ve, ca ve, va ve

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 ty nang o hoi. hieu ((((van cau) OR (toan cau))) or (van dau)) duc ban thanh la ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang o hoi. hieu ((((van cau) OR (toan cau))) OR (van dau)) duc ban thanh la ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang o hoi. hieu ((((van cau) OR (toan cau))) or (van dau)) duc ban thanh la ve triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang o hoi. hieu ((((van cau) OR (toan cau))) or (van dau)) duc ban thanh la ve triet*.