Perhaps you should try some spelling variations:
hoang dai » hoang hai, hoang mai, hoang da
van hoang » van hoan, quan hoang, tran hoang
va trien » va truyen, va thiet, va tuyen
va triet » va thiet, ve triet, cua triet
cam thuc » am thuc, nam thuc, can thuc
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cam thu » nam thu, cac thu, ca thu

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 ky nang xa hoi. hieu va ((cam thuc) or (cam thu)) van hoang dai ((va triet) OR (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang xa hoi. hieu va ((cam thuc) OR (cam thu)) van hoang dai ((va triet) OR (va trien))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang xa hoi. hieu va ((cam thuc) or (cam thu)) van hoang dai ((va triet) OR (va trien))*".