Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hoa lang » hoa dan, hoa van
hieu van » hieu va, thien van, lieu va
benh te » benh tre, benh ve, benh he
nuoc bo » nuoc bao, nuoc bot, nuoc o
quoc bo » quoc bao, quoc co, quoc lo
van lam » van nam
cua tre » cua te, cuu tre, cua triet
o lang » hoi lang
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 ((o lang) OR (hoa lang)) xa hoi. hieu van lam ((quoc bo) or (nuoc bo)) benh te cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((o lang) OR (hoa lang)) xa hoi. hieu van lam ((quoc bo) OR (nuoc bo)) benh te cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((o lang) OR (hoa lang)) xa hoi. hieu van lam ((quoc bo) or (nuoc bo)) benh te cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((o lang) OR (hoa lang)) xa hoi. hieu van lam ((quoc bo) or (nuoc bo)) benh te cua tre*.