Perhaps you should try some spelling variations:
vanh thai » anh thai, van thai, vanh tai
dang xay » dang van, van xay
hieu cua » hieu qua, dieu cua, bieu cua
thai cua » than cua, tai cuc, tri cua
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, lang van
cac hoc » cach hoc, cac hop, bac hoc
va vanh » va van, va danh, va hanh
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) or (dang xay)))) hoi. hieu cua cac hoc va vanh thai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((nang xa) OR (((lang xa) OR (dang xay)))) hoi. hieu cua cac hoc va vanh thai cua te.
• Adding a wildcard symbol may retrieve word variants: te sac ky ((nang xa) or (((lang xa) or (dang xay)))) hoi. hieu cua cac hoc va vanh thai cua te*.