Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
cac xuc » cam xuc, cac nuoc, chat xuc
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va
cao hoc » co hoc, cho hoc, chat hoc
ty nang » ky nang, ty xang, ty hang
cua cau » cua cac, cua chu, cua cay
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: doc sach ty nang cao hoc. ((hieu ve) or (hieu van)) cac xuc ((van hanh) OR (ban hanh)) di cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty nang cao hoc. ((hieu ve) OR (hieu van)) cac xuc ((van hanh) OR (ban hanh)) di cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty nang cao hoc. ((hieu ve) or (hieu van)) cac xuc ((van hanh) OR (ban hanh)) di cua cau*".