Perhaps you should try some spelling variations:
cua quoc » cua nuoc, cua thuoc
ban hanh » ban hang
thuc ban » thuoc ban, thuc dan, thu ban
cam thuc » am thuc, nam thuc, cam thu
hieu van » hieu va, thien van, lieu va
hoi lang » hoa lang, hoi dan
van cam » van nam, van lam, van cau
cua duc » cua tuc, cua nuoc
te sach » toc sach
o lang » hoa lang

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 ((o lang) OR (hoi lang)) xa hoi. hieu van cam thuc ban hanh vi ((cua duc) or (cua quoc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((o lang) OR (hoi lang)) xa hoi. hieu van cam thuc ban hanh vi ((cua duc) OR (cua quoc)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((o lang) OR (hoi lang)) xa hoi. hieu van cam thuc ban hanh vi ((cua duc) or (cua quoc))".
• Adding a wildcard symbol may retrieve word variants: te sach ((o lang) OR (hoi lang)) xa hoi. hieu van cam thuc ban hanh vi ((cua duc) or (cua quoc))*.