Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
xang cho » sang cho, hang cho, tang cho
cac duc » cac du, cao duc, cac nuoc
cac dac » cac dan, cac dai, cac bac
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, xach tay
cho hoc » co hoc, khoa hoc
cua cau » cua cac, cua chu, cua cay
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: te ((sach ty) or (sach thu)) xang cho hoc. hieu ve ((cac duc) OR (cac dac)) van hanh vi cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach thu)) xang cho hoc. hieu ve ((cac duc) OR (cac dac)) van hanh vi cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) or (sach thu)) xang cho hoc. hieu ve ((cac duc) OR (cac dac)) van hanh vi cua cau*".