Perhaps you should try some spelling variations:
cham duc » cham soc, pham duy, phan duc
va trien » va truyen, va thiet, va tuyen
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
va xanh » va danh, va hanh, va anh
xanh di » danh di, vanh dai, xanh tai
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, 5 hoi
di va » dai va, di vao, doi va

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 nang ((x hoi) or (x ho)). hieu ve ((cham duc) or (pham duc)) va xanh di va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((x hoi) OR (x ho)). hieu ve ((cham duc) OR (pham duc)) va xanh di va trien.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((x hoi) or (x ho)). hieu ve ((cham duc) or (pham duc)) va xanh di va trien*.