Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
va triet » va thiet, va trien, ve triet
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
va hanh » van hanh, va thanh, va danh
v nang » va nang, vu nang, van nang
xuc va » duc va, tuc va, luc va
vi va » vi van, vai va, vu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (doc sach)) v nang xa hoi. ((hieu va) or (lieu va)) cam xuc va hanh vi va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) v nang xa hoi. ((hieu va) OR (lieu va)) cam xuc va hanh vi va triet.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) v nang xa hoi. ((hieu va) or (lieu va)) cam xuc va hanh vi va triet*.