Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ty » sach y, sach tu, sach thu
va danh » va dinh, va hanh, dia danh
qua nam » quan nam, cua nam, quang nam
cuu tre » cua tre, cau tren, cau treo
va dan » ca dan, va dao, va dau
ang xa » lang xa, mang xa, dang xay
ty ang » ty xang, ty hang, ty anh
di cuu » di cau, di cua, dinh cuu

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 ty ang xa hoi. hieu qua nam thuc ((((va danh) or (va dan))) or (van hanh)) di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty ang xa hoi. hieu qua nam thuc ((((va danh) OR (va dan))) OR (van hanh)) di cuu tre.
• Adding a wildcard symbol may retrieve word variants: te sach ty ang xa hoi. hieu qua nam thuc ((((va danh) or (va dan))) or (van hanh)) di cuu tre*.