Perhaps you should try some spelling variations:
hanh cong » thanh cong, hang cong, hanh dong
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
thuc day » thuc dan, thuc vat
cong su » cong suc, cong sua, cong cu
sach ky » sac ky, sach y, sach kem
cao hoi » cau hoi, co hoi, cao hoc
sach ty » sach y, sach tu, sach thu
van cam » van nam, van lam, van cau
xuc va » duc va, tuc va, luc va

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

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