Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
van nham » van nam, van nhan, van tham
hieu van » hieu va, thien van, lieu va
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
cao hoi » cau hoi, co hoi, cao hoc
va dan » ca dan, va dao, va dap
va dau » va dao
vai va » mai va, dai va, hai 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) or (thu sach)) ky nang cao hoi. hieu van nham thuc ((va dan) OR (va dau)) vai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang cao hoi. hieu van nham thuc ((va dan) OR (va dau)) vai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang cao hoi. hieu van nham thuc ((va dan) OR (va dau)) vai va thiet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang cao hoi. hieu van nham thuc ((va dan) OR (va dau)) vai va thiet*.