Perhaps you should try some spelling variations:
nha thuoc » nha nuoc, nhan thuc, nha hoc
nam thuoc » nam thuc, nam thu, cay thuoc
cua viet » ca viet, hoa viet, cua vat
dao hanh » dao thanh, dang hanh, ban hanh
sach ty » sach y, sach tu, sach thu
so sach » so sanh, bo sach, co sach
hieu he » hieu ve, hiem he, hieu le
ty tang » tay tang, ty xang, ty hang
ma hoi » mai hoi, ma hoa, me hoi
vi cua » vai cua, di cua

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 ty tang ((ma hoi) or (xa hoi)). hieu he ((nam thuoc) OR (nha thuoc)) dao hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty tang ((ma hoi) OR (xa hoi)). hieu he ((nam thuoc) OR (nha thuoc)) dao hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty tang ((ma hoi) or (xa hoi)). hieu he ((nam thuoc) OR (nha thuoc)) dao hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: so sach ty tang ((ma hoi) or (xa hoi)). hieu he ((nam thuoc) OR (nha thuoc)) dao hanh vi cua viet*.