Perhaps you should try some spelling variations:
sach ty » sach y, sach tu, sach thu
bac may » ban may, bach mai, bac thay
cac bac » cac bai, cac ban, cac cach
su sach » so sach, vu sach
hieu ve » hieu van
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
bi van » bui van, vi van, binh van
x hoi » xa hoi, o hoi, x ho
bi va » bo va

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 ty nang x hoi. ((hieu ve) OR (hieu va)) cac bac may tinh ((bi va) or (bi van)) thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang x hoi. ((hieu ve) OR (hieu va)) cac bac may tinh ((bi va) OR (bi van)) thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang x hoi. ((hieu ve) OR (hieu va)) cac bac may tinh ((bi va) or (bi van)) thiet".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang x hoi. ((hieu ve) OR (hieu va)) cac bac may tinh ((bi va) or (bi van)) thiet*.