Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
van hanh » van thanh, ban hanh, van anh
hoc sach » hoc sinh, hoc cac, hoc anh
tang cho » trang cho, sang cho, hang cho
cac xuc » cac nuoc, chat xuc, cac cuoc
hieu ve » hieu va, hieu van
cua cau » cua cac, cua chu, cua cay
cho hoc » co hoc, khoa hoc
y tang » ky tang, 6 tang, 7 tang
vi cua » vai cua, di cua

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) OR (hoc sach)) y tang cho hoc. hieu ve ((cac xuc) or (cam xuc)) van hanh vi cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) y tang cho hoc. hieu ve ((cac xuc) OR (cam xuc)) van hanh vi cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (hoc sach)) y tang cho hoc. hieu ve ((cac xuc) or (cam xuc)) van hanh vi cua cau*".