Perhaps you should try some spelling variations:
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cao hoi » co hoi, cao hoc, tao hoi
hieu vu » hieu va, hieu ve, hieu su
vu kham » vu khanh
truc va » thuc va, trung va
van dau » van dao, phan dau
dau cua » dai cua, day cua, cau cua
cua tre » cua te, cuu tre, cua triet

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