Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
sach ty » sach y, sach tu, sach thu
sang ma » tang ma, nang ma, sang tao
sach ky » sac ky, sach y, sach kem
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
va hanh » van hanh, va thanh, va danh
ma hoi » mai hoi, xa hoi, ma hoa
cua tu » cua tuc, cua su, cua cu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ky) OR (sach ty)) sang ma hoi. hieu va pham duc va hanh vi ((cua tu) OR (va triet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ky) OR (sach ty)) sang ma hoi. hieu va pham duc va hanh vi ((cua tu) or (va triet))~".
• Adding a wildcard symbol may retrieve word variants: doc ((sach ky) OR (sach ty)) sang ma hoi. hieu va pham duc va hanh vi ((cua tu) or (va triet))*.