Perhaps you should try some spelling variations:
sach ky » sac ky, sach y, sach ty
nang co » nang cao, nang doc, nang noi
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
co hoi » co hoc, co loi
ve bac » ve bao, ve cac, ve ban
bo va » bao va, do va, so va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sach ky) or (cac ky)) nang co hoi. hieu ve bac bo va hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (cac ky)) nang co hoi. hieu ve bac bo va hanh vi ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (cac ky)) nang co hoi. hieu ve bac bo va hanh vi ((cua tre) or (cuu tre))*.