Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
cua tre » cuu tre, cua triet, dua tren
dinh du » dinh duc, dinh cu, dinh tu
va dinh » van dinh, va kinh, va tinh
thuc va » thuc vat, thuc dan, thuc day
hoc sac » hoc sach, hoc cac, hoc mac
thi van » thi lan, thi hanh, thi nang
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, ma hoa
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sac ky sang ma hoi. ((thien van) or (thi van)) tham thuc va dinh du ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sac ky sang ma hoi. ((thien van) OR (thi van)) tham thuc va dinh du ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: hoc sac ky sang ma hoi. ((thien van) or (thi van)) tham thuc va dinh du ((cua tre) or (cua te))*.