Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
nang o » nang co, nang ho, nang ro
ve cac » va cac, vien cac
bo van » vo van, so van, ho van
do van » dao van, vo van, so van
o hoi » co hoi, o hoc, o hai
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang o hoi. hieu ve cac ((bo van) or (do van)) hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang o hoi. hieu ve cac ((bo van) OR (do van)) hanh vi su triet.
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang o hoi. hieu ve cac ((bo van) or (do van)) hanh vi su triet*.