Perhaps you should try some spelling variations:
khien tinh » thien tinh, khien thich, bien tinh
hoc khien » hoc hien, hoc nghien, hoc thieu
doanh cua » doanh luan
nhung don » nhung van, nhung bo
dung cong » dung trong
manh cua » ban cua
dan than » dan chan, ban than, van than
than tap » toan tap, han tap, phan tap

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc khien tinh - hanh ((manh cua) or (doanh cua)) ((nhung don) or (dung cong)) dan than tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc khien tinh - hanh ((manh cua) OR (doanh cua)) ((nhung don) OR (dung cong)) dan than tap.
• Adding a wildcard symbol may retrieve word variants: hoc khien tinh - hanh ((manh cua) or (doanh cua)) ((nhung don) or (dung cong)) dan than tap*.