Perhaps you should try some spelling variations:
nang duoc » ngang duoc, nang doc, nganh duoc
thien van » thi van
lam truoc » lam thuoc, nam truoc, lam truong
van thiet » va thiet, dan thiet, can thiet
truoc xa » truoc xay, truoc bua, truoc dam
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
xa hanh » xa thanh, xa khanh, va hanh

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 duoc si. ((thien van) or (hieu va)) lam truoc xa hanh vi van thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang duoc si. ((thien van) OR (hieu va)) lam truoc xa hanh vi van thiet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang duoc si. ((thien van) or (hieu va)) lam truoc xa hanh vi van thiet*.