Perhaps you should try some spelling variations:
sach doi » sach hoi, sach moi, sach dao
doi nang » dai nang, hoi nang, voi nang
tu sach » thu sach, su sach, te sach
hanh va » hang va
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
cuu tre » cua tre, cau tren, cau treo
xuc va » duc va, tuc va, luc va

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 doi nang xa hoi. ((hieu ve) OR (hieu va)) cam xuc va ((hanh vi) or (hanh va)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach doi nang xa hoi. ((hieu ve) OR (hieu va)) cam xuc va ((hanh vi) OR (hanh va)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach doi nang xa hoi. ((hieu ve) OR (hieu va)) cam xuc va ((hanh vi) or (hanh va)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach doi nang xa hoi. ((hieu ve) OR (hieu va)) cam xuc va ((hanh vi) or (hanh va)) cuu tre*.