Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
pham duy » pham duc
thu nang » thi nang, thu bang, tho nang
thu hang » thi hang, thuc hanh, thu huong
doan van » doan va, hoang van, luan van
tu sach » thu sach, su sach, te sach
ve pham » vi pham, v pham, ve phan
hieu ve » hieu va, hieu van
duy va » duy vat, duy van, day va

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((thu nang) OR (thu hang)) xa hoi. hieu ve pham duy va ((doan van) or (doanh tai)) cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((thu nang) OR (thu hang)) xa hoi. hieu ve pham duy va ((doan van) OR (doanh tai)) cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((thu nang) OR (thu hang)) xa hoi. hieu ve pham duy va ((doan van) or (doanh tai)) cau treo".
• Adding a wildcard symbol may retrieve word variants: tu sach ((thu nang) OR (thu hang)) xa hoi. hieu ve pham duy va ((doan van) or (doanh tai)) cau treo*.