Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
ve triet » su triet
van hanh » van thanh, ban hanh, van anh
tang van » dang van, hoang van, trong van
hanh su » hanh sua, hinh su, hanh tu
so sach » bo sach, co sach, hoc sach
van hoc » van hoa
ty tang » tay tang, ty xang, ty hang
so sanh » do sanh
qua cam » qua cham, qua cac, qua ca
cam so » nam so, ham so, cam lo
so van » su van, vo van

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (so sanh)) ty tang van hoc. hieu qua cam so van hanh su ((ve triet) OR (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) ty tang van hoc. hieu qua cam so van hanh su ((ve triet) OR (va trien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) or (so sanh)) ty tang van hoc. hieu qua cam so van hanh su ((ve triet) OR (va trien))".
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (so sanh)) ty tang van hoc. hieu qua cam so van hanh su ((ve triet) OR (va trien))*.