Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, cam thu
nang ma » tang ma, sang ma, nang cao
van cam » van nam, van lam, van cau
sach ly » sach y, sach lo, sach ty
thuc va » thuc vat, thuc dan, thuc day
va tinh » may tinh
ly nang » ky nang, ly hang, ly vang
hoi cau » hoc cau, hoa cau, hoi cac
hoi chu » hoi chuc
so sach » so sanh, bo sach, co sach
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ly nang ma hoi. hieu van cam thuc va tinh ((hoi cau) or (hoi chu)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ly nang ma hoi. hieu van cam thuc va tinh ((hoi cau) OR (hoi chu)) treo.
• Adding a wildcard symbol may retrieve word variants: so sach ly nang ma hoi. hieu van cam thuc va tinh ((hoi cau) or (hoi chu)) treo*.