Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
thuoc va » thuc va, thuoc ma, thuong va
hieu van » thien van, lieu va, hieu ve
tu sach » thu sach, te sach, tu cach
hieu va » lieu va, hieu qua
vai cua » dai cua, hai cua, lai cua
dan vai » dan va, dan tai, dan vat
cua tre » cua te, cuu tre, cua triet
cao hoi » cau hoi, co hoi, cao hoc
su sach » so sach, vu sach
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: ((tu sach) or (su sach)) ky nang cao hoi. ((hieu van) or (hieu va)) nam thuoc va dan vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang cao hoi. ((hieu van) OR (hieu va)) nam thuoc va dan vai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang cao hoi. ((hieu van) or (hieu va)) nam thuoc va dan vai cua tre*.