Perhaps you should try some spelling variations:
hieu phan » phieu phan, lieu phan, hieu pham
hanh vai » hanh vi, hanh va, hanh tai
sach thu » sach thue, sach thieu, sach tham
dau truc » cau truc, dai truc, doan truc
lang van » dang van, tang van, hoang van
phan dau » phan tu, hang dau
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay
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: tu ((sach ky) or (sach thu)) ((lang xa) OR (lang van)) hoi. hieu phan dau truc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach thu)) ((lang xa) OR (lang van)) hoi. hieu phan dau truc va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach thu)) ((lang xa) OR (lang van)) hoi. hieu phan dau truc va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach thu)) ((lang xa) OR (lang van)) hoi. hieu phan dau truc va hanh vai cua tre*.