Perhaps you should try some spelling variations:
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, lieu va
van cham » van chat, van tham, va cham
te sach » toc sach
nang ma » tang ma, sang ma, nang cao
va sinh » va kinh, vi sinh, hoa sinh
va tinh » may tinh
thai va » thai van
ma hoi » mai hoi, xa hoi, ma hoa
thiet » thieu

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 cham thuc ((va sinh) OR (va tinh)) thai va thiet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach han nang ma hoi. hieu van cham thuc ((va sinh) OR (va tinh)) thai va thiet".
• Adding a wildcard symbol may retrieve word variants: te sach han nang ma hoi. hieu van cham thuc ((va sinh) OR (va tinh)) thai va thiet*.