Perhaps you should try some spelling variations:
hanh than » hanh han, hanh nhan, hanh phan
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
than cua » nhan cua, thai cua, ban cua
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
van bac » van ban, van bao, van hac
xuc van » duc van, luc van, vuc van
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((dang xay) OR (mang may)) hoi. hieu van bac xuc van hanh than cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((dang xay) OR (mang may)) hoi. hieu van bac xuc van hanh than cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((dang xay) OR (mang may)) hoi. hieu van bac xuc van hanh than cua tre*.