Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
xuc va » duc va, tuc va, xac va
luc va » duc va, tuc va, loc va
cua tu » cua tuc, cua su, cua cu

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