Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
hanh di » hanh vi, hanh de, hang di
xuc van » duc van, luc van, vuc van
cac xuc » cam xuc, cac nuoc, chat xuc
cua cau » cua cac, cua chu, cua cay
hieu ve » hieu va
cho hoc » co hoc, khoa hoc
ty nang » ky nang, ty hang, ly nang
di cua » dai cua, doi cua, de cua

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) or (ty xang)) cho hoc. ((hieu ve) OR (hieu van)) cac xuc van hanh di cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty nang) OR (ty xang)) cho hoc. ((hieu ve) OR (hieu van)) cac xuc van hanh di cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty nang) or (ty xang)) cho hoc. ((hieu ve) OR (hieu van)) cac xuc van hanh di cua cau*".