Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cham tuc » nham thuc, pham thuc, tham thuc
cao hoi » cau hoi, co hoi, cao hoc
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
dau cua » day cua, cau cua, dan cua
tuc va » thuc va, truc va, tuc xa
va dan » ca dan, va dao, va dau

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)) ky nang cao hoi. hieu vu cham tuc va dan ((dau cua) or (dai cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang cao hoi. hieu vu cham tuc va dan ((dau cua) OR (dai cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky nang cao hoi. hieu vu cham tuc va dan ((dau cua) or (dai cua)) te".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky nang cao hoi. hieu vu cham tuc va dan ((dau cua) or (dai cua)) te*.