Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
su triet » su tien, ve triet
hanh van » thanh van, khanh van, hanh va
doc sach » hoc sach, nuoc sach, dac sac
toc sach » hoc sach, thuoc sach, nuoc sach
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
su viet » so viet

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) OR (toc sach)) ky nang cao hoi. hieu ve pham thuc va hanh van ((su triet) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc sach) OR (toc sach)) ky nang cao hoi. hieu ve pham thuc va hanh van ((su triet) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc sach) OR (toc sach)) ky nang cao hoi. hieu ve pham thuc va hanh van ((su triet) or (su viet))".
• Adding a wildcard symbol may retrieve word variants: ((doc sach) OR (toc sach)) ky nang cao hoi. hieu ve pham thuc va hanh van ((su triet) or (su viet))*.