Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
thuc day » thuc dan, thuc vat
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
sach ky » sac ky, sach ty, sach kem
hanh di » hanh vi, hanh de, danh di
hang di » hang doi, hang vi, hang dien
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ky) or (sach y)) nang cao hoi. hieu ve pham thuc day ((hanh di) OR (hang di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sach y)) nang cao hoi. hieu ve pham thuc day ((hanh di) OR (hang di)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sach y)) nang cao hoi. hieu ve pham thuc day ((hanh di) OR (hang di)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sach y)) nang cao hoi. hieu ve pham thuc day ((hanh di) OR (hang di)) cua tre*.