Perhaps you should try some spelling variations:
manh thai » manh hai, anh thai, manh khai
thu sach » tu sach, thuat sach, thuoc sach
sach thu » sach thue, sach thieu, sach tham
thai cua » than cua, tai cuc, tri cua
quoc ban » quoc bao, quoc lan, quoc quan
hieu van » hieu va, thien van, lieu va
van lam » van nam
lang xa » lang ha, dang xay, lang van
dang va » dang van, dang vat, hang va
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: thu sach thu ((dang va) or (lang xa)) hoi. hieu van lam ((quoc ban) or (duc tan)) manh thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach thu ((dang va) OR (lang xa)) hoi. hieu van lam ((quoc ban) OR (duc tan)) manh thai cua tre.
• Adding a wildcard symbol may retrieve word variants: thu sach thu ((dang va) or (lang xa)) hoi. hieu van lam ((quoc ban) or (duc tan)) manh thai cua tre*.