Perhaps you should try some spelling variations:
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
cac bac » cac ban, cac cach, sach bac
va tinh » may tinh
tinh vi » trinh vi, tinh voi, tinh va
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho
vi va » vi van, vai va, vu va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang x hoi. hieu ve ((cac bac) OR (cac bai)) va tinh vi va thiet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x hoi. hieu ve ((cac bac) OR (cac bai)) va tinh vi va thiet".
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. hieu ve ((cac bac) OR (cac bai)) va tinh vi va thiet*.