Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, pham thuc
nham thu » nam thu, pham thu, nhan thuc
tu sach » thu sach, su sach, te sach
sach su » cach su, sach tu, sach uu
su dang » su dung
dang ma » dang mau, dang mam, dang mat
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
hanh ki » hanh vi, hanh ky, hanh kien
su viet » so viet
ma hoi » mai hoi, xa hoi, ma hoa
ki su » ky su

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 su dang ma hoi. hieu va ((nham thuc) or (nham thu)) va hanh ki su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach su dang ma hoi. hieu va ((nham thuc) OR (nham thu)) va hanh ki su viet.
• Adding a wildcard symbol may retrieve word variants: tu sach su dang ma hoi. hieu va ((nham thuc) or (nham thu)) va hanh ki su viet*.