Perhaps you should try some spelling variations:
khanh van » thanh van, khanh vinh, hanh va
pham thuc » phap thuc, pham chuc, nham thuc
hieu voi » hieu moi, lieu voi, hieu loi
va khanh » van khanh, va thanh, vu khanh
su triet » su viet, su tien, ve triet
hieu vi » hieu va, hieu ve, hien vi
sach ky » sac ky, sach ty, sach kem
nang ma » tang ma, sang ma, nang cao
thuc va » thuc vat, thuc dan, thuc day
ma hoi » mai hoi, xa hoi, ma hoa
van su » dan 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 (sach y)) nang ma hoi. ((hieu vi) OR (hieu voi)) pham thuc va khanh van su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ky) OR (sach y)) nang ma hoi. ((hieu vi) OR (hieu voi)) pham thuc va khanh van su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ky) or (sach y)) nang ma hoi. ((hieu vi) OR (hieu voi)) pham thuc va khanh van su triet".
• Adding a wildcard symbol may retrieve word variants: doc ((sach ky) or (sach y)) nang ma hoi. ((hieu vi) OR (hieu voi)) pham thuc va khanh van su triet*.