Perhaps you should try some spelling variations:
nam thuoc » nam thu, nha thuoc, cay thuoc
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
nam thuc » am thuc, nam thu, nam tu
vai cua » dai cua, hai cua, lai cua
te sach » toc sach
sach ky » sac ky, sach y, sach ty
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
va dan » ca dan, va dao, va dau

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