Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lam quoc » lam duoc, nam quoc, lam thuoc
hoa lang » hoa dan, hoa van
hieu van » hieu va, thien van, lieu va
bo benh » so benh, o benh, ba benh
quoc bo » quoc bao, nuoc bo, quoc co
van lam » van nam
te cua » le cua, de cua
o lang » hoi lang

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 benh ((te cua) OR (tue 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 benh ((te cua) OR (tue 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 benh ((te cua) OR (tue cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((o lang) or (hoa lang)) xa hoi. hieu van lam quoc bo benh ((te cua) OR (tue cua)) tre*.