Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
nam thuc » nam thuoc, am thuc, nam thu
te sach » toc sach
tai cua » thai cua, tai cuc, tri cua
xa hanh » xa thanh, xa khanh, va hanh
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
sang ma » nang ma, sang tao, mang may
cua tre » cua te, cuu tre, cua triet
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky ((sang ma) or (tang ma)) hoi. hieu va nam thuc ((xa hanh) or (van hanh)) tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((sang ma) OR (tang ma)) hoi. hieu va nam thuc ((xa hanh) OR (van hanh)) tai cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ky ((sang ma) or (tang ma)) hoi. hieu va nam thuc ((xa hanh) or (van hanh)) tai cua tre*.