Perhaps you should try some spelling variations:
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cao duc » dao duc, giao duc, tao duoc
cao suc » cao su
va dung » van dung, va duong, vat dung
sac ky » cac ky, sai ky
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: te ((sach ky) OR (sac ky)) nang xa hoi. hieu va ((cao duc) or (cao suc)) va dung tai cuc te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sac ky)) nang xa hoi. hieu va ((cao duc) OR (cao suc)) va dung tai cuc te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) OR (sac ky)) nang xa hoi. hieu va ((cao duc) or (cao suc)) va dung tai cuc te".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) OR (sac ky)) nang xa hoi. hieu va ((cao duc) or (cao suc)) va dung tai cuc te*.