Perhaps you should try some spelling variations:
lang van » dang van, tang van, hoang van
hieu cua » hieu qua, bieu cua, hieu ca
dieu cua » dieu tra
hanh tai » thanh tai, hang tai, han tai
nang xa » nang x, lang xa, nang ma
cac hoc » cach hoc, cac hop, bac hoc
va hanh » van hanh, va thanh, va danh
tai cua » thai cua, tai cuc, tri cua
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 van)) hoi. ((hieu cua) OR (dieu cua)) cac 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 (lang van)) hoi. ((hieu cua) OR (dieu cua)) cac 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 (lang van)) hoi. ((hieu cua) OR (dieu cua)) cac hoc va hanh tai cua te*".