Perhaps you should try some spelling variations:
thuc day » thuc dan, thuc vat
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
qua cam » qua cham, qua cac, qua ca
luu tre » luu tru, cuu tre, luy tre
ma hoi » mai hoi, xa hoi, ma hoa
vi luu » vi lua

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ma hoi. hieu qua cam ((tuc xa) OR (thuc day)) hanh vi luu tre~.
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ma hoi. hieu qua cam ((tuc xa) or (thuc day)) hanh vi luu tre*.