Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
te sach » toc sach
sach ky » sac ky, sach y, sach ty
doc hai » duc hai, do hai, ngoc hai
hoc hai » hoc dai, hoc bai, hoc tai
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
luu tre » luu tru, cuu tre, luy tre
vi luu » vi lua

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 nang ((doc hai) or (hoc hai)). hieu va cac thuc va hanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((doc hai) OR (hoc hai)). hieu va cac thuc va hanh vi luu tre.
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ((doc hai) or (hoc hai)). hieu va cac thuc va hanh vi luu tre*.