Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
van hanh » van thanh, ban hanh, van anh
va hanh » va thanh, va danh, ban hanh
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
sai ky » sac ky
di cuu » di cau, di cua, dinh cuu
ve cam » ve cham, ve cac, va cam
x hoi » xa hoi, o hoi, x ho

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 (sai ky)) nang x hoi. hieu ve cam thuc ((va hanh) or (van hanh)) di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sai ky)) nang x hoi. hieu ve cam thuc ((va hanh) OR (van hanh)) di cuu tre.
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sai ky)) nang x hoi. hieu ve cam thuc ((va hanh) or (van hanh)) di cuu tre*.