Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
sach thu » sach thue, sach thieu, sach tham
nam thuc » nam thuoc, am thuc, nam thu
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu he » hieu ve, hiem he, hieu le
sach ty » sach y, sach tu, xach tay
ma hoi » mai hoi, ma hoa, me hoi
he nam » ha nam, nghe nam
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) OR (sach thu)) tang ((ma hoi) or (xa hoi)). hieu he nam thuc va hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach ty) OR (sach thu)) tang ((ma hoi) OR (xa hoi)). hieu he nam thuc va hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach ty) OR (sach thu)) tang ((ma hoi) or (xa hoi)). hieu he nam thuc va hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: so ((sach ty) OR (sach thu)) tang ((ma hoi) or (xa hoi)). hieu he nam thuc va hanh vi cua viet*.