Perhaps you should try some spelling variations:
trinh viet » ninh viet, trinh vat
doc thuc » hoc thuc, do thuc, hoc thuoc
trong xa » trong xay, trong ca, trong xu
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
tinh vi » trinh vi, tinh voi, tinh va
van doc » van duoc, van hoc, van loc
thuc va » thuc vat, thuc dan, thuc day
sach ty » sach y, sach tu, sach thu
tang xa » trang xa, tang ma, lang xa
cua tre » cua te, cuu tre, cua triet

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 ty ((tang xa) OR (trong xa)) hoi. hieu van doc thuc va ((tinh vi) OR (trinh viet)) cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((tang xa) OR (trong xa)) hoi. hieu van doc thuc va ((tinh vi) OR (trinh viet)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((tang xa) OR (trong xa)) hoi. hieu van doc thuc va ((tinh vi) OR (trinh viet)) cua tre*.