Perhaps you should try some spelling variations:
so sach » bo sach, co sach, hoc sach
dinh vi » dinh ve, dinh viet, dinh tri
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
so sanh » do sanh
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (so sanh)) ky nang xa hoi. hieu va cam ((luc va) or (tuc va)) dinh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) ky nang xa hoi. hieu va cam ((luc va) OR (tuc va)) dinh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (so sanh)) ky nang xa hoi. hieu va cam ((luc va) or (tuc va)) dinh vi cua tre*.