Perhaps you should try some spelling variations:
danh hai » dang hai, lanh hai, manh hai
hai cua » thai cua, dai cua, hoi cua
duc van » duc va, duc tan, duc manh
duc ban » duc tan, dua ban, duc man
cua tre » cua te, cuu tre, cua triet
sach ky » sach y, sach ty, sach kem
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
sac ky » cac ky, sai ky
va cam » va cham, va cac, va cao

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