Perhaps you should try some spelling variations:
nam thuoc » nam thu, nha thuoc, cay thuoc
toc sach » doc sach, thuoc sach, nuoc sach
nam thuc » am thuc, nam thu, nam tu
hieu van » hieu va, thien van, lieu va
hoc sach » hoc sinh, hoc cac, hoc anh
dang xay » dang van, van xay
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
dan vai » dan va, dan tai, dan vat
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
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: ((toc sach) OR (hoc sach)) ky dang xay hoi. hieu van ((nam thuc) or (nam thuoc)) va dan vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ky dang xay hoi. hieu van ((nam thuc) OR (nam thuoc)) va dan vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (hoc sach)) ky dang xay hoi. hieu van ((nam thuc) or (nam thuoc)) va dan vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (hoc sach)) ky dang xay hoi. hieu van ((nam thuc) or (nam thuoc)) va dan vai cuu tre*.