Perhaps you should try some spelling variations:
va triet » va trien, ve triet, cua triet
hanh vai » hanh vi, hanh va, hanh tai
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
ve nam » he nam, va nam, le nam
thiet » thieu

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 y ((nang ma) OR (sang ma)) hoi. hieu ve nam thuc va hanh vai ((va triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang ma) OR (sang ma)) hoi. hieu ve nam thuc va hanh vai ((va triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang ma) OR (sang ma)) hoi. hieu ve nam thuc va hanh vai ((va triet) or (va thiet))".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang ma) OR (sang ma)) hoi. hieu ve nam thuc va hanh vai ((va triet) or (va thiet))*.