Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
van hanh » van thanh, ban hanh, van anh
doi cua » dai cua, hoi cua, dong cua
va hanh » va thanh, va danh, ban hanh
te sach » toc sach
nang ma » tang ma, nang cao, mang may
sang ma » tang ma, sang tao, mang may
cua tre » cua te, cuu tre, cua triet

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