Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
hanh dan » thanh dan, hanh san, canh dan
sach ky » sach y, sach ty, sach kem
cao hoi » cau hoi, co hoi, cao hoc
hieu vi » hieu voi, hieu va, hieu ve
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
su tien » su kien, su hien, tu tieng
sac ky » cac ky, sai ky
dan su » dang su

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((sach ky) OR (sac ky)) nang cao hoi. hieu vi pham thuc va hanh dan su tien~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ky) OR (sac ky)) nang cao hoi. hieu vi pham thuc va hanh dan su tien".
• Adding a wildcard symbol may retrieve word variants: doc ((sach ky) OR (sac ky)) nang cao hoi. hieu vi pham thuc va hanh dan su tien*.