Perhaps you should try some spelling variations:
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » hieu qua
ky dang » ky nang, ky danh
ma hoi » mai hoi, ma hoa, me hoi
vi cua » vai cua, di cua
cua te » cua tu

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 ky dang ((ma hoi) or (xa hoi)). ((hieu va) or (lieu va)) nam thuc day hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ((ma hoi) OR (xa hoi)). ((hieu va) OR (lieu va)) nam thuc day hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((ma hoi) or (xa hoi)). ((hieu va) or (lieu va)) nam thuc day hanh vi cua te*.