Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hanh va » hang va, hanh vi
duc ban » duc tan, duc van, dua ban
luc bat » suc bat, luc nhat, luat bat
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
va cua » va chua, via cua, ca cua
ve cam » ve cham, ve cac, va cam

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 ((nang xa) or (nang ma)) hoi. hieu ve cam ((luc bat) or (duc ban)) hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang ma)) hoi. hieu ve cam ((luc bat) OR (duc ban)) hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang ma)) hoi. hieu ve cam ((luc bat) or (duc ban)) hanh va cua tre*.