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