Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
cu tren » tu tren, dua tren
va cam » va cham, va cac, va cao
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: ((toc sach) OR (doc sach)) ty nang x ho. hieu va cam xuc va hanh vi ((cua tre) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ty nang x ho. hieu va cam xuc va hanh vi ((cua tre) OR (cu tren))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (doc sach)) ty nang x ho. hieu va cam xuc va hanh vi ((cua tre) or (cu tren))*".