Perhaps you should try some spelling variations:
sach ky » sac ky, sach ty, sach kem
cach tu » cach thuc
ve cach » va cach, ve cac, ve canh
hieu ve » hieu va, hieu van
nang ro » nang co, nang ra, nang rong
nang ho » nang hoc, nang co, tang ho
cua tre » cua te, cuu tre, cua triet
va don » va dong, va doc, va do
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sach y)) ((nang ho) or (nang ro)) hoi. hieu ve cach tu va don vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) ((nang ho) OR (nang ro)) hoi. hieu ve cach tu va don vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) ((nang ho) or (nang ro)) hoi. hieu ve cach tu va don vi cua tre*.