Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, cam thu
cau theo » cau thi, cau tao
sach ly » sach lo, sach ty, sach hay
nang ma » tang ma, sang ma, nang cao
van cam » van nam, van lam, van cau
thuc va » thuc vat, thuc dan, thuc day
dan hai » doan hai, dang hai, dan khai
hai cau » hai chau, hai chu, hai hau
ma hoi » mai hoi, xa hoi, ma hoa
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: su ((sach ly) or (sach y)) nang ma hoi. hieu van cam thuc va dan hai cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ly) OR (sach y)) nang ma hoi. hieu van cam thuc va dan hai cau theo.
• Adding a wildcard symbol may retrieve word variants: su ((sach ly) or (sach y)) nang ma hoi. hieu van cam thuc va dan hai cau theo*.