Perhaps you should try some spelling variations:
thanh sang » thanh san, thanh hang, thanh hoang
van thanh » ban thanh, van tuan
dang xay » dang van, van xay
sang cua » mang cua, song cua, hang cua
dang xa » lang xa, dang ha, dang va
hieu va » lieu va, hieu qua
sat van » sat va, hat van, hoat van
cua tre » cua te, cuu tre, cua triet
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
khao » khac, khai, thao

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky ((dang xa) OR (dang xay)) hoi. hieu va khao sat van thanh sang cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((dang xa) OR (dang xay)) hoi. hieu va khao sat van thanh sang cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((dang xa) OR (dang xay)) hoi. hieu va khao sat van thanh sang cua tre*.