Perhaps you should try some spelling variations:
doc thuc » hoc thuc, do thuc, hoc thuoc
trinh va » trinh van, trinh vat, trinh ve
trong xu » thong xu, trong su, trong thu
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, su sach, vu khach
tinh vi » trinh vi, tinh voi, tinh va
thuc va » thuc vat, thuc dan, thuc day
van doc » van duoc, van hoc, van loc
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: vu sach ty ((tang xa) or (trong xu)) hoi. hieu van doc thuc va ((tinh vi) or (trinh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ty ((tang xa) OR (trong xu)) hoi. hieu van doc thuc va ((tinh vi) OR (trinh va)) cua tre.
• Adding a wildcard symbol may retrieve word variants: vu sach ty ((tang xa) or (trong xu)) hoi. hieu van doc thuc va ((tinh vi) or (trinh va)) cua tre*.