Perhaps you should try some spelling variations:
te sach » toc sach
va hanh » van hanh, va thanh, va danh
va cao » va cac, va co, va dao
nang o » nang co, nang ho, nang ro
ve cai » va cai, ve tai, ve cau
luc va » duc va, tuc va, loc va
y nang » ky nang, ly nang, v nang
ve cac » va cac, vien cac
vi va » vi van, vai va, vu va
o hoi » co hoi, o hoc, o hai
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang o hoi. hieu ((((ve cai) or (ve cac))) or (va cao)) luc va hanh vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang o hoi. hieu ((((ve cai) OR (ve cac))) OR (va cao)) luc va hanh vi va thiet.
• Adding a wildcard symbol may retrieve word variants: te sach y nang o hoi. hieu ((((ve cai) or (ve cac))) or (va cao)) luc va hanh vi va thiet*.