Perhaps you should try some spelling variations:
cay phoi » cap phoi, tay hoi, cay cho
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
vai cuu » vai cua
dan vai » dan va, dan tai, dan vat
thuc va » thuc vat, thuc dan, thuc day
cuu tre » cua tre, cau tren, cau treo
sach ky » sach y, sach ty, sach kem
xay hoi » xa hoi, tay hoi, gay thoi
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: te ((sach ky) or (sac ky)) dang ((xay hoi) OR (cay phoi)). hieu van nam thuc va dan vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sac ky)) dang ((xay hoi) OR (cay phoi)). hieu van nam thuc va dan vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (sac ky)) dang ((xay hoi) OR (cay phoi)). hieu van nam thuc va dan vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) or (sac ky)) dang ((xay hoi) OR (cay phoi)). hieu van nam thuc va dan vai cuu tre*.