Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
hieu van » hieu va, thien van, lieu va
ma thanh » mai thanh, ha thanh, ta thanh
va thanh » gia thanh, ban thanh, va tinh
cao hoi » cau hoi, co hoi, cao hoc
vai cua » dai cua, hai cua, lai cua
sac ky » cac ky, sai ky
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach y) or (sac ky)) nang cao hoi. hieu van nam thuoc ((ma thanh) OR (va thanh)) vai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach y) OR (sac ky)) nang cao hoi. hieu van nam thuoc ((ma thanh) OR (va thanh)) vai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach y) or (sac ky)) nang cao hoi. hieu van nam thuoc ((ma thanh) OR (va thanh)) vai cua tu".
• Adding a wildcard symbol may retrieve word variants: tu ((sach y) or (sac ky)) nang cao hoi. hieu van nam thuoc ((ma thanh) OR (va thanh)) vai cua tu*.