Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
benh tue » benh tre, benh te, benh theo
tue cua » te cua
lang xa » lang ha, dang xay, lang van
bo benh » so benh, o benh, ba benh
quoc bo » quoc bao, nuoc bo, quoc co
van hau » van ha, van hai, van dau
va hau » va chau, vat hau, va dau
y lang » o lang, _ lang, tay lang
cua te » cua tu

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

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