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
vanh dai » van dai, vanh tai, lanh dao
sach ky » sac ky, sach ty, sach kem
xay hoi » xa hoi, tay hoi, cay phoi
thuc va » thuc vat, thuc dan, thuc day
va vanh » va van, va danh, va hanh
cua tre » cuu tre, cua triet, dua tren
cua te » cua tu

You may be able to get more results by adjusting your search query.

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