Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
benh te » benh tre, benh ve, benh he
quoc co » quoc cao, quoc cho, duoc co
quoc bo » quoc bao, nuoc bo, quoc lo
van lam » van nam
lang xa » dang xay, lang van
lang ha » long ha
cua tre » cua te, cuu tre, cua triet
te cua » tue cua, le cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y ((lang xa) OR (lang ha)) hoi. hieu van lam ((quoc bo) or (quoc co)) benh te cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((lang xa) OR (lang ha)) hoi. hieu van lam ((quoc bo) OR (quoc co)) benh te cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y ((lang xa) OR (lang ha)) hoi. hieu van lam ((quoc bo) or (quoc co)) benh te cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y ((lang xa) OR (lang ha)) hoi. hieu van lam ((quoc bo) or (quoc co)) benh te cua tre*.