Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
ve tham » va tham, ve cham, vi tham
tang ma » mang may, tang van
sang ma » nang ma, sang tao, mang may
sac ky » cac ky, sai ky
va dau » va dao
dau vi » dau ve, dau va, dat vi
tu sac » tu sach, tu cac, tu san

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky ((sang ma) or (tang ma)) hoi. hieu ve tham thuc va dau vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((sang ma) OR (tang ma)) hoi. hieu ve tham thuc va dau vi ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((sang ma) or (tang ma)) hoi. hieu ve tham thuc va dau vi ((cua tre) or (cuu tre))*.