Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh dai » hanh tai, hanh dao, vanh dai
nam thuc » nam thuoc, am thuc, nam thu
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, dam thuc
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
tang ma » mang may, tang van
sang ma » nang ma, sang tao, mang may
dai va » mai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky ((sang ma) OR (tang ma)) hoi. hieu va ((cam tuc) or (nam thuc)) va hanh dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((sang ma) OR (tang ma)) hoi. hieu va ((cam tuc) OR (nam thuc)) va hanh dai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((sang ma) OR (tang ma)) hoi. hieu va ((cam tuc) or (nam thuc)) va hanh dai va triet".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((sang ma) OR (tang ma)) hoi. hieu va ((cam tuc) or (nam thuc)) va hanh dai va triet*.