Perhaps you should try some spelling variations:
thanh cac » hanh cac, thanh bac, thanh ca
nang mai » nang ma, nang tai, lang mai
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co 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
luc va » tuc va, loc va
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 y nang mai hoi. hieu van nam ((luc va) OR (duc va)) thanh cac cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y nang mai hoi. hieu van nam ((luc va) OR (duc va)) thanh cac cua te".
• Adding a wildcard symbol may retrieve word variants: so sach y nang mai hoi. hieu van nam ((luc va) OR (duc va)) thanh cac cua te*.