Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
vanh dai » van dai, vanh tai, lanh dao
dang xay » dang van, van xay
cua tre » cuu tre, cua triet, dua tren
va vanh » va van, va danh, va hanh
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
xay hoi » xa hoi, tay hoi, cay phoi
sac ky » cac ky, sai ky
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 y) or (sac ky)) dang xay hoi. hieu va tham thuc va vanh dai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach y) OR (sac ky)) dang xay hoi. hieu va tham thuc va vanh dai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach y) or (sac ky)) dang xay hoi. hieu va tham thuc va vanh dai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach y) or (sac ky)) dang xay hoi. hieu va tham thuc va vanh dai ((cua tre) OR (cua te))*.