Perhaps you should try some spelling variations:
sinh thai » dinh thi
cham thuc » nham thuc, pham thuc, tham thuc
sach han » sach tham, sach danh, sach nang
han nang » phan nang, van nang, ban nang
hieu van » hieu va, thien van, hieu ve
thuc dan » thuc hanh, hoc dan, thuc vat
dan sinh » dang sinh, doan sinh, van sinh
va triet » va thiet, va trien, ve triet
te sach » toc sach
nang ma » tang ma, sang ma, nang cao
thai va » thai van
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: te sach han nang ma hoi. ((hieu van) or (lieu va)) cham thuc dan sinh thai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach han nang ma hoi. ((hieu van) OR (lieu va)) cham thuc dan sinh thai va triet.
• Adding a wildcard symbol may retrieve word variants: te sach han nang ma hoi. ((hieu van) or (lieu va)) cham thuc dan sinh thai va triet*.