Perhaps you should try some spelling variations:
cach hoc » cach thuc, cach thoi, dich hoc
hanh tai » thanh tai, hang tai, han tai
dang xay » dang van, van xay
hieu va » lieu va, hieu qua
nang xa » lang xa, nang ma, mang xa
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
va cach » va cac
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 (nang x))) or (dang xay)) hoi. hieu va cach hoc va hanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((((nang xa) OR (nang x))) OR (dang xay)) hoi. hieu va cach hoc va hanh tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky ((((nang xa) OR (nang x))) or (dang xay)) hoi. hieu va cach hoc va hanh tai cua te".
• Adding a wildcard symbol may retrieve word variants: te sac ky ((((nang xa) OR (nang x))) or (dang xay)) hoi. hieu va cach hoc va hanh tai cua te*.