Perhaps you should try some spelling variations:
cham duc » pham duc, cham soc, pham duy
toan tai » toan tap, doanh tai, toan ban
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
va cham » va chat, va tham
va toan » van toan, bai toan, tap toan
cua tre » cua te, cua triet, dua tren
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) or (hoc sinh)) ky nang xa hoi. lieu va cham duc va toan tai ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (hoc sinh)) ky nang xa hoi. lieu va cham duc va toan tai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (hoc sinh)) ky nang xa hoi. lieu va cham duc va toan tai ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (hoc sinh)) ky nang xa hoi. lieu va cham duc va toan tai ((cua tre) OR (cuu tre))*.