Perhaps you should try some spelling variations:
dinh dien » tinh dien, kinh dien, dich dien
chat hoc » chat hoa, chat thom, cho hoc
dien cuc » dien tu, dieu cua, vien cac
sach va » sach ha, sach dao, sach nha
sach xa » sach dao, sach nha, sach bai
nang xa » nang x, lang xa, nang ma
hieu va » lieu va
va dinh » van dinh, va kinh, va tinh
cuc te » cua te, cuc thue, cuc tieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((sach va) OR (sach xa)) nang xa hoi. ((hieu va) or (hieu qua)) chat hoc va dinh dien cuc te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach va) OR (sach xa)) nang xa hoi. ((hieu va) OR (hieu qua)) chat hoc va dinh dien cuc te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach va) OR (sach xa)) nang xa hoi. ((hieu va) or (hieu qua)) chat hoc va dinh dien cuc te".
• Adding a wildcard symbol may retrieve word variants: toc ((sach va) OR (sach xa)) nang xa hoi. ((hieu va) or (hieu qua)) chat hoc va dinh dien cuc te*.