Perhaps you should try some spelling variations:
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
cau tren » cu tren, dau tren, ca tren
sach ky » sach y, sach ty, sach kem
xay hoi » xa hoi, tay hoi, cay phoi
thuc va » thuc vat, thuc dan, thuc day
dan vat » dang vat, van vat, dan va
vat cau » dat cau, va cau, van cau
sac ky » cac ky, sai ky
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 ky) or (sac ky)) dang xay hoi. hieu van nam thuc va dan vat cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach ky) OR (sac ky)) dang xay hoi. hieu van nam thuc va dan vat cau tren.
• Adding a wildcard symbol may retrieve word variants: toc ((sach ky) or (sac ky)) dang xay hoi. hieu van nam thuc va dan vat cau tren*.