Perhaps you should try some spelling variations:
su viet » so viet
va phan » van phan, va phat, va phap
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
su tien » su kien, su hien, tu tieng
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
va han » van han, va hanh, va hang
dam tu » nam tu, cam tu, tam tu
va dam » van dam, va dao, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky nang xa hoi. hieu va dam tu ((va han) OR (va phan)) tai ((su tien) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky nang xa hoi. hieu va dam tu ((va han) OR (va phan)) tai ((su tien) OR (su viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky nang xa hoi. hieu va dam tu ((va han) OR (va phan)) tai ((su tien) or (su viet))".
• Adding a wildcard symbol may retrieve word variants: te sac ky nang xa hoi. hieu va dam tu ((va han) OR (va phan)) tai ((su tien) or (su viet))*.