Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
hieu van » hieu va, thien van, lieu va
thanh vi » hanh vi, thanh va, thanh ve
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
van am » van nam, van lam, van dam
vi hoa » voi hoa, vi hoc, va hoa
thuc » 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 dang ((xa hoi) or (ma hoa)). hieu van am thuc vat thanh vi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky dang ((xa hoi) OR (ma hoa)). hieu van am thuc vat thanh vi hoa viet.
• Adding a wildcard symbol may retrieve word variants: so sach ky dang ((xa hoi) or (ma hoa)). hieu van am thuc vat thanh vi hoa viet*.