Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
van cam » van nam, van cau, van dam
van lam » van nam
han tai » hang tai, nhan tai, van tai
luc va » tuc va, loc va
tai va » thai va, mai va, tri 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: tu sach ky nang cao hoi. hieu ((van cam) or (van lam)) ((luc va) or (duc va)) han tai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cao hoi. hieu ((van cam) OR (van lam)) ((luc va) OR (duc va)) han tai va thiet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang cao hoi. hieu ((van cam) or (van lam)) ((luc va) or (duc va)) han tai va thiet*.