Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
su triet » su viet, su tien, ve triet
thanh va » hanh va, thanh ha, thanh ve
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
cac bac » cac bai, cac ban, cac cach
tu sach » thu sach, su sach, te sach
cac tac » cac toc, cac dac, cac tai
ty nang » ky nang, ty xang, ty hang
nang o » nang co, nang ho, nang ro
o hai » co hai, so hai, o lai

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 hai. hieu van ((cac tac) OR (cac bac)) xa ((thanh va) or (thanh van)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang o hai. hieu van ((cac tac) OR (cac bac)) xa ((thanh va) OR (thanh van)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang o hai. hieu van ((cac tac) OR (cac bac)) xa ((thanh va) or (thanh van)) su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang o hai. hieu van ((cac tac) OR (cac bac)) xa ((thanh va) or (thanh van)) su triet*.