Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
khach tu » khach deu, khanh thu, hanh tu
trinh vi » trinh va, trinh ve, trinh viet
trong xa » trong xay, trong ca, trong xu
hoc thuc » hoc huu
tinh vi » tinh voi, tinh va, dinh vi
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
tang xa » trang xa, tang ma, lang xa
ve hoc » te hoc, va hoc, vi hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu khach tu ((tang xa) or (trong xa)) hoi. hieu ve hoc thuc vat ((tinh vi) or (trinh vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu khach tu ((tang xa) OR (trong xa)) hoi. hieu ve hoc thuc vat ((tinh vi) OR (trinh vi)) cua tre.
• Adding a wildcard symbol may retrieve word variants: vu khach tu ((tang xa) or (trong xa)) hoi. hieu ve hoc thuc vat ((tinh vi) or (trinh vi)) cua tre*.