Perhaps you should try some spelling variations:
lam thuoc » nam thuoc, am thuc, cay thuoc
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
thuoc va » thuc va, thuoc ma, thuong va
hang di » hang doi, hang vi, hang dien
hanh di » hanh vi, hanh de, danh di
tu sach » thu sach, te sach, tu cach
de hang » de dang, de tang, de bang
su sach » so sach, vu sach
van lam » van nam
va hoa » van hoa, va hoc, ma hoa

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) or (su sach)) de hang va hoa. hieu van lam thuoc va ((hanh di) OR (hang di)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) de hang va hoa. hieu van lam thuoc va ((hanh di) OR (hang di)) cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) de hang va hoa. hieu van lam thuoc va ((hanh di) OR (hang di)) cua viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) de hang va hoa. hieu van lam thuoc va ((hanh di) OR (hang di)) cua viet*.