Perhaps you should try some spelling variations:
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
cac hoc » cach hoc, cac hop, bac hoc
hanh di » hanh vi, hanh de, danh di
hang di » hang doi, hang vi, hang dien
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
cua te » cua tu

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) or (lang xa)) hoi. hieu va cac hoc va ((hanh di) OR (hang di)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((nang xa) OR (lang xa)) hoi. hieu va cac hoc va ((hanh di) OR (hang di)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky ((nang xa) or (lang xa)) hoi. hieu va cac hoc va ((hanh di) OR (hang di)) cua te".
• Adding a wildcard symbol may retrieve word variants: te sac ky ((nang xa) or (lang xa)) hoi. hieu va cac hoc va ((hanh di) OR (hang di)) cua te*.