Perhaps you should try some spelling variations:
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, va danh
sang ma » tang ma, nang ma, sang tao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
sai ky » sac ky
ve cam » ve cham, ve cac, va cam
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 (sai ky)) sang ma hoi. hieu ((ve cam) or (va cac)) duc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sai ky)) sang ma hoi. hieu ((ve cam) OR (va cac)) duc va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sai ky)) sang ma hoi. hieu ((ve cam) or (va cac)) duc va hanh vi cua tre*.