Perhaps you should try some spelling variations:
thanh cac » hanh cac, thanh bac, thanh ca
ban thanh » ban hanh, ban hang
nang mai » nang ma, nang tai, lang mai
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, nam thu, nam tu
so sach » so sanh, bo sach, hoc sach
co sach » bo sach, cuon sach, hoc sach
mai hoi » mai khoi, dai hoi, lai hoi
cac cua » cach cua, cac qua, ca cua
y nang » ky nang, ly nang, v nang
cua te » cua tu

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 mai hoi. hieu van ((nam thuc) OR (am thuc)) ban thanh cac cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (co sach)) y nang mai hoi. hieu van ((nam thuc) OR (am thuc)) ban thanh cac cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) or (co sach)) y nang mai hoi. hieu van ((nam thuc) OR (am thuc)) ban thanh cac cua te".
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (co sach)) y nang mai hoi. hieu van ((nam thuc) OR (am thuc)) ban thanh cac cua te*.