Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va triet » va thiet, va trien, ve triet
nang xa » nang x, lang xa, nang ma
cao suc » cao su, cao duc
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
v nang » va nang, vu nang, van nang
sach v » sach va, sach y, sach 2
suc va » duc va, tuc va, luc va
ve va » ve van, te va, ke 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 v nang xa hoi. ((((hieu va) or (hieu qua))) or (lieu va)) cao suc va hanh ve va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach v nang xa hoi. ((((hieu va) OR (hieu qua))) OR (lieu va)) cao suc va hanh ve va triet.
• Adding a wildcard symbol may retrieve word variants: toc sach v nang xa hoi. ((((hieu va) or (hieu qua))) or (lieu va)) cao suc va hanh ve va triet*.