Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
toc sach » hoc sach, doc sach, thuoc sach
sach tu » sach thu, cach tu, sach ty
tu nang » tru nang, tu nong, tu nano
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
thuc va » thuc vat, thuc dan, thuc day
dinh vi » dinh ve, dinh viet, dinh tri
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach tu nang ma hoi. hieu ve pham thuc va ((dinh vi) or (chinh tri)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tu nang ma hoi. hieu ve pham thuc va ((dinh vi) OR (chinh tri)) cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach tu nang ma hoi. hieu ve pham thuc va ((dinh vi) or (chinh tri)) cua tre*.