Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
tinh ca » tinh cao, tinh cua, tinh va
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
hieu va » lieu va, hieu qua
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
tuc va » truc va, tuc xa, duc va
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky dang xa hoi. ((hieu ve) or (hieu va)) coc ((tuc va) OR (thuc va)) tinh ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky dang xa hoi. ((hieu ve) OR (hieu va)) coc ((tuc va) OR (thuc va)) tinh ca cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky dang xa hoi. ((hieu ve) or (hieu va)) coc ((tuc va) OR (thuc va)) tinh ca cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky dang xa hoi. ((hieu ve) or (hieu va)) coc ((tuc va) OR (thuc va)) tinh ca cua tre*.