Perhaps you should try some spelling variations:
thi hanh » thi thanh
kem thuc » ket thuc, kien thuc, diem thuc
hanh hai » thanh hai, nhanh hai, hang hai
te sach » toc sach
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet

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 ky ((tang ma) or (hang va)) hoi. thi hanh kem thuc va hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((tang ma) OR (hang va)) hoi. thi hanh kem thuc va hanh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ky ((tang ma) or (hang va)) hoi. thi hanh kem thuc va hanh hai cua tre*.