Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
dinh vi » dinh ve, dinh viet, dinh tri
hieu va » lieu va, hieu qua
va chat » van chat, va phat, cao chat
ty hang » ly hang, ty xang, thi hang
ty nang » ky nang, ty xang, ly nang
lua tre » cua tre, luy tre, dua tren
luc va » duc va, tuc va
loc va » hoc va
vi lua » vi luu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((ty nang) or (ty hang)) xa hoi. hieu va chat ((luc va) OR (loc va)) dinh vi lua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty hang)) xa hoi. hieu va chat ((luc va) OR (loc va)) dinh vi lua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) or (ty hang)) xa hoi. hieu va chat ((luc va) OR (loc va)) dinh vi lua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) or (ty hang)) xa hoi. hieu va chat ((luc va) OR (loc va)) dinh vi lua tre*.