Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
cao hoi » cau hoi, co hoi, cao hoc
van cau » van dau, van hau, van chat
truc va » thuc va, thuc vat, trung va
dan vai » dan va, dan tai, dan vat
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau

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) or (vu khach)) ky nang cao hoi. hieu van cau truc va dan vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu khach)) ky nang cao hoi. hieu van cau truc va dan vai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu khach)) ky nang cao hoi. hieu van cau truc va dan vai cua tre*.