Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hieu vien » hieu viec, thieu nien, hieu tieng
ve triet » va trien, su triet
vat hanh » vat thanh, van hanh, va hanh
hoc vat » hoc va, hoc viet, thuc vat
cac hoc » cach hoc, cac hop, bac hoc
su sach » so sach, vu sach
nang xa » lang xa, nang ma, mang xa
vi ve » va ve, gi ve, ve ve

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 y ((nang xa) OR (nang x)) hoi. ((hieu vien) or (hieu hien)) cac hoc vat hanh vi ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (nang x)) hoi. ((hieu vien) OR (hieu hien)) cac hoc vat hanh vi ve triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) OR (nang x)) hoi. ((hieu vien) or (hieu hien)) cac hoc vat hanh vi ve triet".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) OR (nang x)) hoi. ((hieu vien) or (hieu hien)) cac hoc vat hanh vi ve triet*.