Perhaps you should try some spelling variations:
sach tu » sach thu, cach tu, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va
cac duc » cac du, cao duc, cac dac
va hanh » van hanh, va thanh, va danh
su tien » su kien, su hien, tu tieng
sac ky » cac ky, sai ky
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach tu) or (sac ky)) nang xa hoi. ((hieu va) or (hieu qua)) cac duc va hanh vi su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tu) OR (sac ky)) nang xa hoi. ((hieu va) OR (hieu qua)) cac duc va hanh vi su tien.
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) or (sac ky)) nang xa hoi. ((hieu va) or (hieu qua)) cac duc va hanh vi su tien*.