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

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 hat ((van thanh) OR (van tuan)) sang cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((dang xa) OR (dang xay)) hoi. hieu va khao hat ((van thanh) OR (van tuan)) 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 hat ((van thanh) OR (van tuan)) sang cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((dang xa) or (dang xay)) hoi. hieu va khao hat ((van thanh) OR (van tuan)) sang cua tre*.