Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
v nang » va nang, vu nang, van nang
xuc va » duc va, tuc va, luc va
di va » dai va, di vao, doi 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) or (doc sach)) v nang xa hoi. ((hieu va) or (lieu va)) cam xuc va danh di va thiet~.
• 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 danh di va thiet.
• 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 danh di va thiet*.