Perhaps you should try some spelling variations:
phan duc » pham duc, phan tu, phan dau
kiem thu » kieu thu, kien thuc, diem thuc
lang van » dang van, tang van, hoang van
kiem su » kiem sat, kiet suc
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
hieu ke » hieu kem, chieu ke, hieu ky
ke phan » ve phan, kenh phan, ke thang

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 y ((nang x) or (lang van)) hoi. hieu ke phan duc va hanh ((kiem su) OR (kiem thu)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang x) OR (lang van)) hoi. hieu ke phan duc va hanh ((kiem su) OR (kiem thu)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang x) or (lang van)) hoi. hieu ke phan duc va hanh ((kiem su) OR (kiem thu)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang x) or (lang van)) hoi. hieu ke phan duc va hanh ((kiem su) OR (kiem thu)) triet*.