Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, lieu vien
toc sach » hoc sach, doc sach, thuoc sach
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
cac dac » cac dan, cac dai, cac bac
cua cau » cua cac, cua chu, cua cay
sach ty » sach y, sach tu, sach thu
cac duc » cac du, cao duc, cac cuoc
nang co » nang cao, nang doc, nang noi
ty nang » ky nang, ty xang, ty hang

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