Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
va chat » van chat, va phat, cao chat
danh vi » hanh vi, dinh vi, danh di
cu tren » tu tren, dua tren
luc va » tuc va, loc va
vi cu » vi su, vi xu, vi du

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 ((nang x) or (nang ma)) hoi. hieu va chat ((luc va) or (duc va)) danh vi cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang x) OR (nang ma)) hoi. hieu va chat ((luc va) OR (duc va)) danh vi cu tren.
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang x) or (nang ma)) hoi. hieu va chat ((luc va) or (duc va)) danh vi cu tren*.