Perhaps you should try some spelling variations:
thieu bien » thieu nien, tieu bieu, hien bien
bien cac » vien cac, dien cac, bien ca
cac truc » cau truc, cac tru, cac trung
ve triet » va trien, su triet
hanh tai » thanh tai, hang tai, han tai
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
te sach » toc sach
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ((ky lang) OR (ky dang)) xa hoi. thieu bien cac truc va hanh tai ((ve triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ky lang) OR (ky dang)) xa hoi. thieu bien cac truc va hanh tai ((ve triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ky lang) OR (ky dang)) xa hoi. thieu bien cac truc va hanh tai ((ve triet) or (va thiet))".
• Adding a wildcard symbol may retrieve word variants: te sach ((ky lang) OR (ky dang)) xa hoi. thieu bien cac truc va hanh tai ((ve triet) or (va thiet))*.