Perhaps you should try some spelling variations:
trong van » trong cac
qua pham » quan pham, quy pham, qua cham
tang van » dang van, hoang van, tang luan
sanh thu » sach thu, san thu, doanh thu
duy van » duy vat, dung van
so sanh » do sanh
duy va » duy vat, day va, duy v
vi cua » vai cua, di cua
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: so sanh thu ((tang van) or (trong van)) hoi. hieu qua pham ((duy va) OR (duy van)) hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh thu ((tang van) OR (trong van)) hoi. hieu qua pham ((duy va) OR (duy van)) hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sanh thu ((tang van) or (trong van)) hoi. hieu qua pham ((duy va) OR (duy van)) hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: so sanh thu ((tang van) or (trong van)) hoi. hieu qua pham ((duy va) OR (duy van)) hanh vi cua te*.