Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
hieu vien » hieu hien, thieu nien, hieu tieng
su triet » su viet, su tien, ve triet
vat hanh » vat thanh, van hanh, va hanh
cac hoc » cach hoc, cac hop, bac hoc
hoc vat » hoc va, hoc viet, thuc vat
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
su hien » su kien, su tien, thu hien
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ma hoi. ((hieu vien) or (hieu viec)) cac hoc vat hanh vi ((su triet) or (su hien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. ((hieu vien) OR (hieu viec)) cac hoc vat hanh vi ((su triet) OR (su hien)).
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. ((hieu vien) or (hieu viec)) cac hoc vat hanh vi ((su triet) or (su hien))*.