Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
dang xay » dang van, van xay
van hanh » van thanh, ban hanh, van anh
cham tu » pham tu, chai tu, chay tu
vai cua » dai cua, hai cua, lai cua
xay hoi » xa hoi, tay hoi, cay phoi
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
cam tu » cam thu, nam tu, dam tu
y dang » ky dang, 2 dang, _ dang

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)) y dang xay hoi. hieu ve ((cham tu) OR (cam tu)) van hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y dang xay hoi. hieu ve ((cham tu) OR (cam tu)) van hanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) y dang xay hoi. hieu ve ((cham tu) OR (cam tu)) van hanh vai cua tre*".