Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
lam duoc » nam duoc, luat duoc, lam thuoc
thanh ca » thanh cha, thanh cac, thanh ha
ma thanh » mai thanh, va thanh, ha thanh
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, hoc sach
cao hoi » cau hoi, co hoi, cao hoc
co sach » bo sach, cuon sach, hoc sach
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ca cua » co cua

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

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