Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang mai » nang ma, nang tai, lang mai
hanh ve » hanh vi, hanh va, hanh kem
hoi dan » hoa dan, hoc dan, hoi dap
hoi ban » hoi bai, doi ban, hoc ban
va cham » va chat, va tham
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
ve cua » le cua, de cua, te cua
cua te » cua tu

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