Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
nang cai » nang cao, nang tai, nang cap
cam luc » cam xuc, cau luc
tai cua » thai cua, tai cuc, tri cua
va hanh » va thanh, va danh, ban hanh
cua tre » cua te, cuu tre, cua triet
sach ky » sach y, sach ty, sach kem
hieu va » lieu va, hieu qua
cai hoi » cau hoi, dai hoi, cai hoa
sac ky » cac ky, sai ky
va cam » va cham, va cac, va cao

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 (sac ky)) nang cai hoi. hieu va cam luc ((va hanh) or (van hanh)) tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sac ky)) nang cai hoi. hieu va cam luc ((va hanh) OR (van hanh)) tai cua tre.
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sac ky)) nang cai hoi. hieu va cam luc ((va hanh) or (van hanh)) tai cua tre*.