Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
cam tuc » cam tu, nam thuc, dam thuc
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
cu tren » tu tren, dua tren

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 ty nang x ho. hieu va ((cam tuc) OR (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 ty nang x ho. hieu va ((cam tuc) OR (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 ty nang x ho. hieu va ((cam tuc) OR (cam xuc)) va hanh vi ((cua tre) or (cu tren))*".