Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hang di » hang doi, hang vi, hang dien
hanh di » hanh vi, hanh de, danh di
cam tuc » cam xuc, cam tu, nam thuc
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
ty hang » ly hang, ty xang, thi hang
va hoi » xa hoi, va hoc, va hoa
tuc va » thuc va, truc va, tuc xa
va cam » va cham, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ty hang va hoi. hieu va cam tuc va ((hanh di) or (hang di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ty hang va hoi. hieu va cam tuc va ((hanh di) OR (hang di)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ty hang va hoi. hieu va cam tuc va ((hanh di) or (hang di)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ty hang va hoi. hieu va cam tuc va ((hanh di) or (hang di)) cua tre*.