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