Perhaps you should try some spelling variations:
danh sai » dung sai, danh bat, danh dau
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cau tuc » cau truc, cau tu, cau luc
cua tre » cua te, cua triet, dua tren
xa danh » va danh, dia danh, nam danh
van cau » van dau, van hau, van chat
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
cuu tre » cau tren, cau treo

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 lang) or (ky dang)) xa hoi. hieu van cau tuc xa danh sai ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky dang)) xa hoi. hieu van cau tuc xa danh sai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) or (ky dang)) xa hoi. hieu van cau tuc xa danh sai ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) or (ky dang)) xa hoi. hieu van cau tuc xa danh sai ((cua tre) OR (cuu tre))*.