Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
vat hanh » vat thanh, van hanh, va hanh
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
te sach » toc sach
sang ma » tang ma, nang ma, sang tao
hieu he » hieu ve, hiem he, hieu le
hanh va » hang va, hanh vi
he nam » ha nam, nghe nam

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