Perhaps you should try some spelling variations:
thuc dang » thuoc dang, thuc dan, thuc dung
dang hanh » dang thanh, ban hanh, dang van
va triet » va trien, ve triet, cua triet
nam thuc » nam thuoc, am thuc, nam thu
so sach » so sanh, bo sach, co sach
sang ma » nang ma, sang tao, mang may
tang ma » mang may, tang van
hanh va » hang va, hanh vi
hieu ve » hieu va, hieu van
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: so sach y ((sang ma) OR (tang ma)) hoi. hieu ve nam thuc dang hanh va ((va triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((sang ma) OR (tang ma)) hoi. hieu ve nam thuc dang hanh va ((va triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y ((sang ma) OR (tang ma)) hoi. hieu ve nam thuc dang hanh va ((va triet) or (va thiet))".
• Adding a wildcard symbol may retrieve word variants: so sach y ((sang ma) OR (tang ma)) hoi. hieu ve nam thuc dang hanh va ((va triet) or (va thiet))*.