Perhaps you should try some spelling variations:
trinh tai » trinh toan, trinh tu, trinh han
thu sach » tu sach, thuat sach, thuoc sach
sach tu » sach thu, cach tu, sach ty
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
xuc va » tuc va, luc va, xac va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach tu ((hang va) or (lang xa)) hoi. hieu va cam ((xuc va) OR (duc va)) trinh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach tu ((hang va) OR (lang xa)) hoi. hieu va cam ((xuc va) OR (duc va)) trinh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach tu ((hang va) or (lang xa)) hoi. hieu va cam ((xuc va) OR (duc va)) trinh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach tu ((hang va) or (lang xa)) hoi. hieu va cam ((xuc va) OR (duc va)) trinh tai cua tre*.