Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
sach thi » sach thu, sach tai, sach thieu
thi sang » thi nang, thi hang, thi song
thuc dan » thuc hanh, hoc dan, thuc vat
thuc day » thuc vat
vu sach » vu bach, su sach, vu khach
sang ma » tang ma, nang ma, sang tao
hieu ve » hieu va, hieu van
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach thi sang ma hoi. ((hieu ve) or (hieu qua)) nam ((thuc day) OR (thuc dan)) hanh vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach thi sang ma hoi. ((hieu ve) OR (hieu qua)) nam ((thuc day) OR (thuc dan)) hanh vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach thi sang ma hoi. ((hieu ve) or (hieu qua)) nam ((thuc day) OR (thuc dan)) hanh vi cua triet".
• Adding a wildcard symbol may retrieve word variants: vu sach thi sang ma hoi. ((hieu ve) or (hieu qua)) nam ((thuc day) OR (thuc dan)) hanh vi cua triet*.