Perhaps you should try some spelling variations:
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va hanh » van hanh, va thanh, va danh
sai ky » sac ky
de su » den su, ve su, de tu
da su » dan su, dat su, va 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 ky) or (sai ky)) nang xa hoi. hieu va cac duc va hanh ((de su) or (da su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sai ky)) nang xa hoi. hieu va cac duc va hanh ((de su) OR (da su)) triet.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sai ky)) nang xa hoi. hieu va cac duc va hanh ((de su) or (da su)) triet*.