Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
bach toc » bach tuoc, cac toc, bach hoa
thanh va » thanh van, hanh va, thanh ha
cau treo » cau theo, cau tren, cau triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
bac hoc » bai hoc, bac ho
cua tre » cua te, cuu tre, cua triet

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 tang xa hoi. hieu vien ((bach toc) OR (bac hoc)) gia thanh va ((cau treo) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky tang xa hoi. hieu vien ((bach toc) OR (bac hoc)) gia thanh va ((cau treo) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky tang xa hoi. hieu vien ((bach toc) OR (bac hoc)) gia thanh va ((cau treo) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky tang xa hoi. hieu vien ((bach toc) OR (bac hoc)) gia thanh va ((cau treo) or (cua tre))*.