Perhaps you should try some spelling variations:
nang dau » hang dau, xang dau, nang du
thien va » thien van, tien va, thien tai
chat soc » cham soc, chat hoc, chat doc
va thanh » gia thanh, ban thanh, va tinh
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
dau hoi » cau hoi, dai hoi, dan hoi
va chat » van chat, va phat, cao chat
va hanh » van hanh, va danh, ban 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 dau hoi. thien va chat soc ((va hanh) or (va thanh)) lai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang dau hoi. thien va chat soc ((va hanh) OR (va thanh)) lai su triet.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang dau hoi. thien va chat soc ((va hanh) or (va thanh)) lai su triet*.