Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
cao hoc » co hoc, cho hoc, chat hoc
ty nang » ky nang, ty xang, ty hang
cua cau » cua cac, cua chu, cua cay
anh ve » hanh ve, anh viet, thanh ve
anh va » hanh va

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