Perhaps you should try some spelling variations:
phan may » phan xay, phan day, phan giay
phan mai » phan dai, phan bai, phan hai
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
ve cam » ve cham, ve cac, va cam
xuc va » duc va, tuc va, luc va
thiet » thieu

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 xa) or (nang ma)) hoi. hieu ve cam xuc va ((phan mai) OR (phan may)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (nang ma)) hoi. hieu ve cam xuc va ((phan mai) OR (phan may)) va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (nang ma)) hoi. hieu ve cam xuc va ((phan mai) OR (phan may)) va thiet".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (nang ma)) hoi. hieu ve cam xuc va ((phan mai) OR (phan may)) va thiet*.