Perhaps you should try some spelling variations:
sach duy » sach dung, sach duoc, sach dao
tham soc » cham soc, tham nuoc, thai son
van tham » van thanh, van tuan, van chat
hieu van » hieu va, thien van, lieu va
danh vi » hanh vi, dinh vi, danh di
va danh » va dinh, va dan, va hanh
so sach » so sanh, bo sach, co sach
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
su viet » so viet
soc va » hoc va, loc va, doc va
vi su » va su, ve su, ki su

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 duy ((sang ma) OR (nang ma)) hoi. hieu van tham soc va danh vi su viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach duy ((sang ma) OR (nang ma)) hoi. hieu van tham soc va danh vi su viet".
• Adding a wildcard symbol may retrieve word variants: so sach duy ((sang ma) OR (nang ma)) hoi. hieu van tham soc va danh vi su viet*.