Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
hieu van » thien van, lieu va, hieu ve
thuoc va » thuc va, thuoc ma, thuong va
hai cua » thai cua, dai cua, hoi cua
dan hai » doan hai, dang hai, dan khai
hieu va » lieu va, hieu qua
tu sach » thu sach, te sach, tu cach
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
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 sang ma hoi. ((hieu van) or (hieu va)) nam thuoc va dan hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky sang ma hoi. ((hieu van) OR (hieu va)) nam thuoc va dan hai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky sang ma hoi. ((hieu van) or (hieu va)) nam thuoc va dan hai cua tre*.