Perhaps you should try some spelling variations:
trinh vat » trinh van, trinh luat, sinh vat
su sach » so sach, vu sach
coc tuc » coc luc, hoc thuc, doc thuc
tinh va » tich va, trinh van, tinh gia
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
hieu ve » hieu van
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
tuc va » thuc va, truc va, tuc xa

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 ((tinh va) OR (trinh vat)) 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 ((tinh va) OR (trinh vat)) 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 ((tinh va) OR (trinh vat)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky dang xa hoi. ((hieu ve) or (hieu va)) coc tuc va ((tinh va) OR (trinh vat)) cua tre*.