Perhaps you should try some spelling variations:
chat hoc » chat hoa, chat thom, vat hoc
dau cuoi » dam cuoi, dau co, dao cuoc
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu vu » hieu va, hieu ve, hieu su
dau cuu » dau cua
cho hoc » co hoc, khoa hoc
te sac » te sach, te cac, te san
va han » va phan, van han, va hanh
sac ky » cac ky, sai ky

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 lang xa hoi. hieu vu ((chat hoc) OR (cho hoc)) va han ((dau cuu) or (dau cuoi)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky lang xa hoi. hieu vu ((chat hoc) OR (cho hoc)) va han ((dau cuu) OR (dau cuoi)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky lang xa hoi. hieu vu ((chat hoc) OR (cho hoc)) va han ((dau cuu) or (dau cuoi)) tre".
• Adding a wildcard symbol may retrieve word variants: te sac ky lang xa hoi. hieu vu ((chat hoc) OR (cho hoc)) va han ((dau cuu) or (dau cuoi)) tre*.